chore: Update golang to v1.14.12 [backport to release-1.7]

[jannfis]

Back-port of #4832 against release-1.7 branch.

Signed-off-by: jannfis jann@mistrust.net

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• Optional. My organization is added to USERS.md.
• I've signed the CLA and my build is green (troubleshooting builds).

[codecov-io]

Codecov Report

Merging #4834 (8e516e6) into release-1.7 (ad4b60a) will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff              @@
##           release-1.7    #4834   +/-   ##
============================================
  Coverage        41.07%   41.07%           
============================================
  Files              124      124           
  Lines            16577    16577           
============================================
  Hits              6809     6809           
  Misses            8786     8786           
  Partials           982      982           

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[jannfis]

Codegen step fails because of image tag in manifests (tag in branch vs. latest), should be fine.