Split the regex into multiple line to clean up lint error

Author: shahmishal

utils/update_checkout/update_checkout/update_checkout.py

@@ -700,7 +700,10 @@ 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+)'
+        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+)'
         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]