feat: honour GITEA_RUNNER_LABELS on daemon start and accept labels containing a colon (#1085)

Fixes #648
Fixes #656
Fixes #664

---------

Co-authored-by: silverwind <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1085
Reviewed-by: silverwind <[email protected]>

internal/app/cmd/register.go

@@ -387,7 +387,10 @@ func doRegister(ctx context.Context, cfg *config.Config, inputs *registerInputs)
 
 	ls := make([]string, len(reg.Labels))
 	for i, v := range reg.Labels {
-		l, _ := labels.Parse(v)
+		l, err := labels.Parse(v)
+		if err != nil {
+			return fmt.Errorf("failed to parse label %q: %w", v, err)
+		}
 		ls[i] = l.Name
 	}
 	// register new runner.