Update to protolude 0.3.0

The good part is that protolude 0.3.0 builds with GHC 8.10.

The bad part is that this change is a bit painful:
- the default `toS` has changed to no longer convert to and from ByteString
- similarly, `show` no longer outputs ByteString

The changes here are pretty much minimal to keep things compiling; I didn't
see a nice way to work with the new ConvertText class, even though `toUtf8`
seems like it might help if used besides `toS` at just the right spots.

src/PostgREST/Middleware.hs

@@ -27,7 +27,8 @@ import PostgREST.Config       (AppConfig (..), corsPolicy)
 import PostgREST.Error        (SimpleError (JwtTokenInvalid, JwtTokenMissing),
                                errorResponseFor)
 import PostgREST.QueryBuilder (setLocalQuery, setLocalSearchPathQuery)
-import Protolude              hiding (head)
+import Protolude              hiding (head, toS)
+import Protolude.Conv         (toS)
 
 runWithClaims :: AppConfig -> JWTAttempt ->
                  (ApiRequest -> H.Transaction Response) ->