Refine default grep pattern in workflow error script

This commit updates the default regular expression for the
`--grep-pattern` argument in the `print_workflow_run_errors.py` script.

The default pattern is changed from `"[Ee]rror[: ]"` to
`"[Ee][Rr][Rr][Oo][Rr][: ]"` for more specific matching of "Error"
(case-insensitive) followed by a colon or space.

Author: google-labs-jules[bot]

scripts/print_workflow_run_errors.py

@@ -159,8 +159,8 @@ def parse_repo_url_arg(url_string):
   parser.add_argument(
       "--grep-pattern", "-g",
       type=str,
-      default="[Ee]rror[: ]",
-      help="Extended Regular Expression (ERE) to search for in logs. Default: \"[Ee]rror[: ]\". If an empty string is passed, grep is disabled."
+      default="[Ee][Rr][Rr][Oo][Rr][: ]",
+      help="Extended Regular Expression (ERE) to search for in logs. Default: \"[Ee][Rr][Rr][Oo][Rr][: ]\". If an empty string is passed, grep is disabled."
   )
   parser.add_argument(
       "--grep-context", "-C",