Update golang to 1.16.12

What does this MR do?

Updates golang version for the recent golang security release: https://go.dev/doc/devel/release#go1.16

Related issues

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

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Integration tests added to GitLab QA
• The impact any change in container size has should be evaluated