go.mk: lint with staticcheck

[sauterp]

Description

Checklist

(For exoscale contributors)

• [x] Changelog updated (under Unreleased block)
• [ ] For a new resource or new attributes: test added/updated

Testing

❯ make lint
'/home/sauterp/bin/go' install honnef.co/go/tools/cmd/staticcheck@2023.1.7
'/home/sauterp/go/bin/staticcheck' \
   \
  ./...