chore(cabal): update haskell language edition to GHC2021

This includes a good set of default language extensions that are
often used by us. It frees us of explicitly importing common extensions.

Ref: https://ghc.gitlab.haskell.org/ghc/doc/users_guide/exts/control.html#extension-GHC2021

Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>

src/library/PostgREST/ApiRequest/QueryParams.hs

@@ -4,8 +4,7 @@
 --
 -- This module is in charge of parsing all the querystring values in an url, e.g.
 -- the select, id, order in `/projects?select=id,name&id=eq.1&order=id,name.desc`.
-{-# LANGUAGE LambdaCase    #-}
-{-# LANGUAGE TupleSections #-}
+{-# LANGUAGE LambdaCase #-}
 module PostgREST.ApiRequest.QueryParams
   ( parse
   , QueryParams(..)

src/library/PostgREST/App.hs

@@ -9,12 +9,10 @@ Some of its functionality includes:
 - Producing HTTP Headers according to RFCs.
 - Content Negotiation
 -}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE LambdaCase          #-}
-{-# LANGUAGE NamedFieldPuns      #-}
-{-# LANGUAGE RecordWildCards     #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE ViewPatterns        #-}
+{-# LANGUAGE LambdaCase      #-}
+{-# LANGUAGE NamedFieldPuns  #-}
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE ViewPatterns    #-}
 module PostgREST.App
   ( postgrest
   , run

src/library/PostgREST/Auth.hs

@@ -10,7 +10,6 @@ Authentication should always be implemented in an external service.
 In the test suite there is an example of simple login function that can be used for a
 very simple authentication system inside the PostgreSQL database.
 -}
-{-# LANGUAGE FlexibleContexts #-}
 module PostgREST.Auth
   ( getAuthResult )
   where

src/library/PostgREST/Auth/Jwt.hs

@@ -4,8 +4,6 @@ Description : PostgREST JWT support functions.
 
 This module provides functions to deal with JWT parsing and validation (http://jwt.io).
 -}
-{-# LANGUAGE DeriveGeneric         #-}
-{-# LANGUAGE FlexibleContexts      #-}
 {-# LANGUAGE ImpredicativeTypes    #-}
 {-# LANGUAGE LambdaCase            #-}
 {-# LANGUAGE NamedFieldPuns        #-}

src/library/PostgREST/Auth/JwtCache.hs

@@ -4,13 +4,9 @@ Description : PostgREST JWT validation results Cache.
 
 This module provides functions to deal with the JWT cache.
 -}
-{-# LANGUAGE ExistentialQuantification #-}
-{-# LANGUAGE FlexibleContexts          #-}
-{-# LANGUAGE FlexibleInstances         #-}
-{-# LANGUAGE LambdaCase                #-}
-{-# LANGUAGE MultiParamTypeClasses     #-}
-{-# LANGUAGE NamedFieldPuns            #-}
-{-# LANGUAGE StrictData                #-}
+{-# LANGUAGE LambdaCase     #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE StrictData     #-}
 
 module PostgREST.Auth.JwtCache
   ( init

src/library/PostgREST/Cache/Sieve.hs

@@ -8,11 +8,9 @@ This module provides implementation of a mutable cache on Sieve algorithm.
 {-# LANGUAGE GADTs           #-}
 {-# LANGUAGE LambdaCase      #-}
 {-# LANGUAGE NamedFieldPuns  #-}
-{-# LANGUAGE PolyKinds       #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE RecursiveDo     #-}
 {-# LANGUAGE StrictData      #-}
-{-# LANGUAGE TupleSections   #-}
 
 module PostgREST.Cache.Sieve (
       Cache

src/library/PostgREST/Config.hs

@@ -3,13 +3,10 @@ Module      : PostgREST.Config
 Description : Manages PostgREST configuration type and parser.
 
 -}
-{-# LANGUAGE FlexibleContexts      #-}
-{-# LANGUAGE FlexibleInstances     #-}
-{-# LANGUAGE LambdaCase            #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE RecordWildCards       #-}
+{-# LANGUAGE LambdaCase      #-}
+{-# LANGUAGE RecordWildCards #-}
 {-# OPTIONS_GHC -fno-warn-type-defaults #-}
-{-# LANGUAGE NamedFieldPuns        #-}
+{-# LANGUAGE NamedFieldPuns  #-}
 
 module PostgREST.Config
   ( AppConfig (..)

src/library/PostgREST/Config/PgVersion.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE DeriveAnyClass #-}
-{-# LANGUAGE DeriveGeneric  #-}
 module PostgREST.Config.PgVersion
   ( PgVersion(..)
   , minimumPgVersion

src/library/PostgREST/MediaType.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE DeriveAnyClass        #-}
-{-# LANGUAGE DeriveGeneric         #-}
 {-# LANGUAGE DuplicateRecordFields #-}
 {-# OPTIONS_GHC -Wno-unused-do-bind #-}
 module PostgREST.MediaType

src/library/PostgREST/Observation.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE DeriveGeneric #-}
 {-|
 Module      : PostgREST.Observation
 Description : This module holds an Observation type which is the core of Observability for PostgREST.

src/library/PostgREST/SchemaCache.hs

@@ -8,15 +8,10 @@ The schema cache is necessary for resource embedding, foreign keys are used for
 
 These queries are executed once at startup or when PostgREST is reloaded.
 -}
-{-# LANGUAGE DeriveAnyClass        #-}
-{-# LANGUAGE DeriveGeneric         #-}
-{-# LANGUAGE FlexibleContexts      #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE NamedFieldPuns        #-}
-{-# LANGUAGE QuasiQuotes           #-}
-{-# LANGUAGE RecordWildCards       #-}
-{-# LANGUAGE ScopedTypeVariables   #-}
-{-# LANGUAGE TypeSynonymInstances  #-}
+{-# LANGUAGE DeriveAnyClass  #-}
+{-# LANGUAGE NamedFieldPuns  #-}
+{-# LANGUAGE QuasiQuotes     #-}
+{-# LANGUAGE RecordWildCards #-}
 
 module PostgREST.SchemaCache
   ( SchemaCache(..)

src/library/PostgREST/SchemaCache/Identifiers.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE DeriveAnyClass #-}
-{-# LANGUAGE DeriveGeneric  #-}
 
 module PostgREST.SchemaCache.Identifiers
   ( FieldName

src/library/PostgREST/SchemaCache/Relationship.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE DeriveAnyClass #-}
-{-# LANGUAGE DeriveGeneric  #-}
 
 module PostgREST.SchemaCache.Relationship
   ( Cardinality(..)

src/library/PostgREST/SchemaCache/Representations.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE DeriveAnyClass #-}
-{-# LANGUAGE DeriveGeneric  #-}
 
 module PostgREST.SchemaCache.Representations
   ( DataRepresentation(..)

src/library/PostgREST/SchemaCache/Routine.hs

@@ -1,6 +1,4 @@
-{-# LANGUAGE DeriveAnyClass     #-}
-{-# LANGUAGE DeriveGeneric      #-}
-{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE DeriveAnyClass #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 
 module PostgREST.SchemaCache.Routine

src/library/PostgREST/SchemaCache/Table.hs

@@ -1,6 +1,4 @@
-{-# LANGUAGE DeriveAnyClass    #-}
-{-# LANGUAGE DeriveGeneric     #-}
-{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE DeriveAnyClass #-}
 
 module PostgREST.SchemaCache.Table
   ( Column(..)