[test, don't merge].golangci.yml: reenable nilness check

[tarasmadan]

experimental

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (d9b1cdd) 62.7% compared to head (67a462a) 62.7%. Report is 6 commits behind head on dependabot/go_modules/golang.org/x/tools-0.18.0.

Additional details and impacted files

see 1 file with indirect coverage changes