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