Use Go v1.16.12

What does this MR do?

This is a security release of go, see: https://go.dev/doc/devel/release#go1.16

Part of https://gitlab.com/groups/gitlab-org/-/epics/7111

TODO

• I added the Changelog trailer (e.g. Changelog: added) to the commits that need to be included in the changelog
• I added unit tests or they are not required
• I added acceptance tests or they are not required
• I added documentation (or it's not required)
• I followed code review guidelines
• I followed Go Style guidelines