ci/gha: use go test -exec sudo

Running "sudo go test" results in a different environment, so go has to
recompile everything again.

Use "go test -exec sudo" so test would compile as current user (so that
go build cache is reused), then run as root.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

.github/workflows/main.yml

@@ -23,7 +23,7 @@ jobs:
       shell: bash
 
     - name: Test
-      run: sudo -E env PATH=$PATH go test -v ./ ./nl
+      run: go test -exec sudo -v ./ ./nl
 
   build-macos:
     # netlink is Linux-only, but this ensures that netlink builds without error