Relax version bounds for megaparsec

[cideM]

While trying to make tasklite build in nixpkgs I noticed that simple-sql-parser requires megaparsec to be <9.7. Maybe there's a good reason for that, but the Haskell package set in nixpkgs has now moved to megaparsec 9.7, and as such simple-sql-parser fails to build.

simple-sql-parser seems to compile and run its full test suite with megaparsec 9.7, so maybe the version boundaries can be relaxed a bit?

[JakeWheat]

Sorry for the delay. Thanks for the report. Later versions of megaparsec should almost always be fine if they compile and pass the tests. I'll see if I can update the hackage version deps.