Allow year update skipping

update-license/main.go

@@ -63,6 +63,8 @@ const (
 var (
 	flagDryRun = flag.Bool("dry", false, "Do not edit files and just print out what files would be edited")
 
+	flagSkipYearUpdate = flag.Bool("skip-year-update", true, "Ignore updating header if only change is year")
+
 	lineSkipPrefixes = []string{
 		"// Code generated by",
 		"// @generated",
@@ -141,6 +143,9 @@ func updateLines(lines []string, year int) []string {
 			break
 		}
 		if strings.HasPrefix(line, headerPrefix) {
+			if *flagSkipYearUpdate {
+				return lines
+			}
 			lines[i] = headerString(year)
 			return lines
 		}