chore: enable GHC NumericUnderscores language extension

The `_` character between numeric literals improve their readablity.

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

src/PostgREST/AppState.hs

@@ -371,7 +371,7 @@ retryingSchemaCacheLoad appState@AppState{stateObserver=observer, stateMainThrea
       let delayMicroseconds = 32*oneSecondInUs {-32 seconds-} in
       capDelay delayMicroseconds $ exponentialBackoff oneSecondInUs
 
-    oneSecondInUs = 1000000 -- one second in microseconds
+    oneSecondInUs = 1_000_000 -- one second in microseconds
 
 newSchemaCacheStatus :: IO SchemaCacheStatus
 newSchemaCacheStatus = SchemaCacheStatus <$> newEmptyTMVarIO

src/PostgREST/Listener.hs

@@ -97,7 +97,7 @@ retryingListen appState nextDelay hasDbListenerBug = do
   where
     observer = AppState.getObserver appState
     mainThreadId = AppState.getMainThreadId appState
-    oneSecondInMicro = 1000000
+    oneSecondInMicro = 1_000_000
     maxDelay = 32
 
     handleNotification channel msg =

src/PostgREST/Logger.hs

@@ -52,7 +52,7 @@ data LoggerState = LoggerState
 init :: IO LoggerState
 init = mdo
   let
-    oneSecond = 1000000
+    oneSecond = 1_000_000
     loggerState = LoggerState zTime debouncePoolTimeout
   zTime <- mkAutoUpdate defaultUpdateSettings { updateAction = getZonedTime }
   debouncePoolTimeout <- makeDebouncer $