ERROR ConnectionError when requesting from the server

It has been reported that one could get the following error:


when running `ohsome2label vector` from the server.

We found out this issue was related to the security certificate check in Python requests, especially via the server traffic.

One easy solution/walkaround is to change the following code in your repo:

https://github.com/GIScience/ohsome2label/blob/592186653a3be5b0977636c25e5c5eb1bd3bb94a/ohsome2label/utils.py#L22

just to disable the verification, while a better solution should be considered in the future:

`r = requests.get(api, params, verify=False)`