Link to constants.go on master branch

[arve0]

Got confused constants.go had no changes since last summer. Line number is unlikely to change (has not in a year).

Description

Relevant issues/tickets

Type of change

• Documentation improvement
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• This change requires a documentation update
• I have added tests that prove my fix is effective or that my feature works
• I have added a test case that will be used to verify my changes
• Verified independently on a cluster by reviewer

Verification steps

Check that link works and that file is updated last year.