Set Go 1.16.4 for project

What does this MR do?

Sets Go version for in an asdf context to the latest stable.

Allows GDK to roll forward also: gitlab-development-kit!1972 (merged).

TODO

• Added the Changelog (e.g. Changelog: feature) trailer to the commits that need to be included in the changelog
• Added unit tests (if required)
• Added acceptance tests (if required)
• Documentation (if required)
• Code review guidelines
• Go Style guidelines