Python client rejected

[trawler]

Describe the bug
Several URLs return 403 permission denied / connection reset. This could be due to a web application firewall detecting a python client.

• 2022-03-22 12:33:47,222 - error - failed to fetch url https://warmes-bett.de/. error: http error 403: forbidden
• 2022-03-22 12:36:35,740 - error - url: https://hireforukraine.org/ - some other error happened: <urlopen error [errno 104] connection reset by peer>
• 2022-03-22 12:37:02,270 - error - failed to fetch url https://warmes-bett.de/bett-anfragen/. error: http error 403: forbidden
• 2022-03-22 12:37:04,966 - error - failed to fetch url https://warmes-bett.de/bett-anbieten/. error: http error 403: forbidden
• 2022-03-22 12:38:29,868 - error - url: https://hireforukraine.org/ - some other error happened: <urlopen error [errno 104] connection reset by peer>

We need to examine the exact cause and determine which headers would work.