destatis api does not work due to SSLError

Hello,
when trying to use the destatis api (`timeseries_data` to be exact), it throws a SSLCertVerificationError.

`MaxRetryError: HTTPSConnectionPool(host='www-genesis.destatis.de', port=443): Max retries exceeded with url: /genesisWS/rest/2020/data/timeseries?username=*******&password=******* (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self signed certificate in certificate chain (_ssl.c:997)')))`

My code is just the example for `timeseries_data`, with a valid username and password provided.
The host url is `https://www-genesis.destatis.de/genesisWS/rest/2020`.

Start with the `timeseries_data` example and the stated Destatis host URL, reproducing the `SSLCertVerificationError` with valid credentials. Trace the request path and its HTTPS certificate handling; done means the certificate failure has a confirmed resolution or documented cause.

Written by the indexing model from the issue text.