add //go:build directives to prevent downgrading to go1.16 language

[thaJeztah]

- What I did

- How I did it

- How to verify it

- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.29%. Comparing base (c962084) to head (2815d23).
Report is 2 commits behind head on master.

Additional details and impacted files

@@ Coverage Diff @@## master #5803 +/- ##
==========================================
+ Coverage 59.26% 59.29% +0.02% 
==========================================
Files 353 353 Lines 29540 29540 ==========================================
+ Hits 17508 17516 +8 + Misses 11052 11043 -9 - Partials 980 981 +1 

[thaJeztah]

tested with #4723 and looks OK