src: update for changed map type in aeson-2

This means that we're now using Data.Map.Strict instead of
Data.HashMap.Strict for JSON objects in general, and specifically
for claims maps and CSV rows.

This addresses certain hash flooding vulnerabilities, but may
have performance downsides.

Compare e.g. https://frasertweedale.github.io/blog-fp/posts/2021-10-12-aeson-hash-flooding-protection.html

src/PostgREST/Middleware.hs

@@ -10,6 +10,8 @@ module PostgREST.Middleware
   ) where
 
 import qualified Data.Aeson                        as JSON
+import qualified Data.Aeson.Key                    as K
+import qualified Data.Aeson.KeyMap                 as KM
 import qualified Data.ByteString.Lazy.Char8        as LBS
 import qualified Data.HashMap.Strict               as HM
 import qualified Data.Text                         as T
@@ -38,7 +40,7 @@ import PostgREST.Request.Preferences
 import Protolude
 
 -- | Runs local(transaction scoped) GUCs for every request, plus the pre-request function
-runPgLocals :: AppConfig   -> HM.HashMap Text JSON.Value -> Text ->
+runPgLocals :: AppConfig   -> KM.KeyMap JSON.Value -> Text ->
                (ApiRequest -> ExceptT Error SQL.Transaction Wai.Response) ->
                ApiRequest  -> ByteString -> PgVersion -> ExceptT Error SQL.Transaction Wai.Response
 runPgLocals conf claims role app req jsonDbS actualPgVersion = do
@@ -57,7 +59,7 @@ runPgLocals conf claims role app req jsonDbS actualPgVersion = do
                    then setConfigLocal "request.cookie." <$> iCookies req
                    else setConfigLocalJson "request.cookies" (iCookies req)
     claimsSql = if usesLegacyGucs
-                  then setConfigLocal "request.jwt.claim." <$> [(toUtf8 c, toUtf8 $ unquoted v) | (c,v) <- HM.toList claims]
+                  then setConfigLocal "request.jwt.claim." <$> [(toUtf8 $ K.toText c, toUtf8 $ unquoted v) | (c,v) <- KM.toList claims]
                   else [setConfigLocal mempty ("request.jwt.claims", LBS.toStrict $ JSON.encode claims)]
     roleSql = [setConfigLocal mempty ("role", toUtf8 role)]
     appSettingsSql = setConfigLocal mempty <$> (join bimap toUtf8 <$> configAppSettings conf)