$GITHUB_PATH support (#566)

* Regression in the .golangci.yml file

* This looks like an even better fix to #451

The previous solution only prevented the `starting container process caused "exec: \"bash\"`
error when someone added an "extra" path in the workflow using `::add-path`

* Add support for >> $GITHUB_PATH

* The newRunCommand has too high cyclomatic complexity

* Add "linux/arm64" to new test

* The cyclop linter was complaining so I extracted some funcs

* Close some readers

* Fix typo

* fix: add missing composite function

* Fix regress from merging

* Keep the error messages as is

* consolidate with master

* Close the tar reader on defer

* New way to get ContainerWorkdir

* Remove arch from runner test

* Separate the UpdateFromEnv and UpdateFromPath

Co-authored-by: hackercat <me@hackerc.at>

pkg/runner/run_context.go

@@ -154,6 +154,10 @@ func (rc *RunContext) startJobContainer() common.Executor {
 				Name: "workflow/envs.txt",
 				Mode: 0644,
 				Body: "",
+			}, &container.FileEntry{
+				Name: "workflow/paths.txt",
+				Mode: 0644,
+				Body: "",
 			}),
 		)(ctx)
 	}
@@ -628,6 +632,7 @@ func (rc *RunContext) withGithubEnv(env map[string]string) map[string]string {
 	github := rc.getGithubContext()
 	env["CI"] = "true"
 	env["GITHUB_ENV"] = "/tmp/workflow/envs.txt"
+	env["GITHUB_PATH"] = "/tmp/workflow/paths.txt"
 	env["GITHUB_WORKFLOW"] = github.Workflow
 	env["GITHUB_RUN_ID"] = github.RunID
 	env["GITHUB_RUN_NUMBER"] = github.RunNumber