build: fix string compare for SortFunc (#29595)

build/update-license.go

@@ -291,8 +291,8 @@ func writeAuthors(files []string) {
 		}
 	}
 	// Write sorted list of authors back to the file.
-	slices.SortFunc(list, func(a, b string) bool {
-		return strings.ToLower(a) < strings.ToLower(b)
+	slices.SortFunc(list, func(a, b string) int {
+		return strings.Compare(strings.ToLower(a), strings.ToLower(b))
 	})
 	content := new(bytes.Buffer)
 	content.WriteString(authorsFileHeader)