Upgrade hamlit and haml_lint for Rails 6 support

What does this MR do?

For hamlit:

https://github.com/k0kubun/hamlit/compare/v2.8.8...v2.10.0

https://github.com/k0kubun/hamlit/blob/master/CHANGELOG.md

https://github.com/k0kubun/hamlit/pull/138 is the fix we need because without it, the job outputs are too noisy.

For haml:

https://github.com/haml/haml/blob/master/CHANGELOG.md

https://github.com/haml/haml/compare/v5.0.4...v5.1.2

We needed https://github.com/haml/haml/pull/1008 for Rails 6

This change is less important because we only have this as a dependency of haml_lint and we actually use hamlit for rendering.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

#33408 (closed)