update-pr-preview often failing #19378
Description
The "Synchronize the Pull Request Preview / update-pr-preview" check has been failing on many pull requests lately:
#19048
#19209 (comment)
#19323 (comment)
#19370 (comment)
All of them fail like in https://github.com/web-platform-tests/wpt/pull/19048/checks?check_run_id=221550321:
INFO:__main__:Issuing request: GET https://api.github.com/repos/web-platform-tests/wpt/collaborators/LukeZielinski
INFO:__main__:Adding label
INFO:__main__:Issuing request: POST https://api.github.com/repos/web-platform-tests/wpt/issues/19048/labels
Traceback (most recent call last):
File "tools/ci/update_pr_preview.py", line 253, in <module>
code = main(sys.argv[1])
File "tools/ci/update_pr_preview.py", line 225, in main
github.add_label(pr_number, active_label)
File "tools/ci/update_pr_preview.py", line 161, in add_label
request(url, 'post', json_data=data)
File "tools/ci/update_pr_preview.py", line 65, in request
resp.raise_for_status()
File "/usr/local/lib/python2.7/dist-packages/requests/models.py", line 940, in raise_for_status
raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 403 Client Error: Forbidden for url: https://api.github.com/repos/web-platform-tests/wpt/issues/19048/labels
##[error]Docker run failed with exit code 1