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/Private/QueryFragment.hs

@@ -16,7 +16,8 @@ import qualified Data.Text                     as T (map, null,
                                                      takeWhile)
 import           PostgREST.Types
 import           Protolude                     hiding (cast,
-                                                intercalate, replace)
+                                                intercalate, replace,
+                                                toLower)
 import           Text.InterpolatedString.Perl6 (qc)
 
 noLocationF :: SqlFragment