Release gitlab-experiment version 0.6.4

Release of version 0.6.4.

Review the complete diff at: https://gitlab.com/gitlab-org/gitlab-experiment/-/compare/v0.6.3...release-0.6.4

• Checklist before merging:
  • Diff link is up-to-date and working.
  • The version has been adjusted according to SemVer.
  • Release notes are accurate.
  • Gitlab project has been updated and CI is passing.

This MR is generated by an automated release process. If you'd like to add additional information to the MR description, please do, but keep your changes to the area above the changelog, as that can be replaced by the automation process.

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0.6.4 Changelog

• Make fully Ruby 3.0 compatible
• Fix handling of namespaces in from_param