Fix the lint issue

Author: shahmishal

utils/update_checkout/update_checkout/update_checkout.py

@@ -701,9 +701,9 @@ def main():
     cross_repos_pr = {}
     if github_comment:
         regex_pr = r'(apple/[-a-zA-Z0-9_]+/pull/\d+'\
-                    '|apple/[-a-zA-Z0-9_]+#\d+'\
-                    '|swiftlang/[-a-zA-Z0-9_]+/pull/\d+'\
-                    '|swiftlang/[-a-zA-Z0-9_]+#\d+)'
+            r'|apple/[-a-zA-Z0-9_]+#\d+'\
+            r'|swiftlang/[-a-zA-Z0-9_]+/pull/\d+'\
+            r'|swiftlang/[-a-zA-Z0-9_]+#\d+)'
         repos_with_pr = re.findall(regex_pr, github_comment)
         print("Found related pull requests:", str(repos_with_pr))
         repos_with_pr = [pr.replace('/pull/', '#') for pr in repos_with_pr]