feat: deprecate github-actions format (#4726)

pkg/config/loader.go

@@ -350,6 +350,13 @@ func (l *Loader) handleDeprecation() error {
 		l.cfg.Output.Formats = f
 	}
 
+	for _, format := range l.cfg.Output.Formats {
+		if format.Format == OutFormatGithubActions {
+			l.log.Warnf("The output format `%s` is deprecated, please use `%s`", OutFormatGithubActions, OutFormatColoredLineNumber)
+			break // To avoid repeating the message if there are several usages of github-actions format.
+		}
+	}
+
 	l.handleLinterOptionDeprecations()
 
 	return nil

pkg/config/output.go

@@ -17,7 +17,7 @@ const (
 	OutFormatCodeClimate       = "code-climate"
 	OutFormatHTML              = "html"
 	OutFormatJunitXML          = "junit-xml"
-	OutFormatGithubActions     = "github-actions"
+	OutFormatGithubActions     = "github-actions" // Deprecated
 	OutFormatTeamCity          = "teamcity"
 	OutFormatSarif             = "sarif"
 )

pkg/printers/githubaction.go

@@ -15,6 +15,7 @@ type GitHubAction struct {
 }
 
 // NewGitHubAction output format outputs issues according to GitHub actions.
+// Deprecated
 func NewGitHubAction(w io.Writer) *GitHubAction {
 	return &GitHubAction{w: w}
 }