feat: support schema version bumps in the lexer

[ewanharris]

Description

This makes the lexer support parsing schema as multiple digits rather than a hardcoded 1.1, some tests have been removed as they are now valid syntax but as this is now being moved to validation they can't be handled in a cross language way due to lack of validation in Go.

References

Closes #55

Review Checklist

• [x] I have clicked on "allow edits by maintainers".
• [ ] I have added documentation for new/changed functionality in this PR or in a PR to openfga.dev [Provide a link to any relevant PRs in the references section above]
• [x] The correct base branch is being used, if not main
• [ ] I have added tests to validate that the change in functionality is working as expected

[rhamzeh]

@ewanharris can you rebase of main, so that the go build works?