bin/gitlab_gql: fix command in example

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26141>

bin/ci/gitlab_gql.py

@@ -472,7 +472,7 @@ def parse_args() -> Namespace:
         formatter_class=ArgumentDefaultsHelpFormatter,
         description="CLI and library with utility functions to debug jobs via Gitlab GraphQL",
         epilog=f"""Example:
-        {Path(__file__).name} --print-job-dag""",
+        {Path(__file__).name} --print-dag""",
     )
     parser.add_argument("-pp", "--project-path", type=str, default="mesa/mesa")
     parser.add_argument("--sha", "--rev", type=str, default='HEAD')