Update OpenAPI client and extend mypy checks

[robin-nitrokey]

This patch updates the OpenAPI client using the generator version 3.1.1.
It also removes the mypy config that ignored errors for the generated
code as the new generator version fixes the mypy issues in it.

Fixes: #39

[codecov]

Codecov Report

Attention: 39 lines in your changes are missing coverage. Please review.

Comparison is base (f9006e6) 79.80% compared to head (b65d6a9) 79.31%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #42      +/-   ##
==========================================
- Coverage   79.80%   79.31%   -0.50%     
==========================================
  Files         782      782              
  Lines       13712    13382     -330     
==========================================
- Hits        10943    10614     -329     
+ Misses       2769     2768       -1     

Files	Coverage Δ
nethsm/client/api_response.py	100.00% <100.00%> (ø)
...ient/components/schema/backup_passphrase_config.py	87.50% <ø> (ø)
nethsm/client/components/schema/decrypt_data.py	75.00% <ø> (ø)
...m/client/components/schema/decrypt_request_data.py	78.26% <100.00%> (ø)
...m/client/components/schema/encrypt_request_data.py	78.26% <100.00%> (ø)
...thsm/client/components/schema/health_state_data.py	71.87% <ø> (ø)
nethsm/client/components/schema/info_data.py	72.22% <100.00%> (ø)
...ent/components/schema/key_generate_request_data.py	74.24% <100.00%> (ø)
nethsm/client/components/schema/key_item.py	71.87% <ø> (ø)
...ethsm/client/components/schema/key_private_data.py	66.07% <100.00%> (ø)
... and 289 more

... and 89 files with indirect coverage changes

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