chore: use the same .golangci.yml as the runner & gofumpt over gofmt (#206)

To prepare for a smooth merge in the runner codebase.

- run with --fix for gofumpt and golangci
- manual edits for
  - disabling useless package naming warning
  - rename variables that had underscore in their name
  - remove trailing else at the end of a few functions

Reviewed-on: https://code.forgejo.org/forgejo/act/pulls/206
Reviewed-by: Michael Kriese <michael.kriese@gmx.de>
Co-authored-by: Earl Warren <contact@earl-warren.org>
Co-committed-by: Earl Warren <contact@earl-warren.org>

act/runner/action_test.go

@@ -122,7 +122,7 @@ runs:
 
 			writeFile := func(filename string, data []byte, perm fs.FileMode) error {
 				assert.Equal(t, "actionDir/actionPath/trampoline.js", filename)
-				assert.Equal(t, fs.FileMode(0400), perm)
+				assert.Equal(t, fs.FileMode(0o400), perm)
 				return nil
 			}