Vault-env can write files

[ewjoachim]

Closes #185

Successful PR Checklist:

• Tests (units, integration, 100% coverage)
  • (not applicable?)
• Documentation
  • (not applicable?)
• Had a good time contributing?

[codecov]

Codecov Report

Merging #186 (4e075d4) into master (8505388) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #186   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           13        13           
  Lines          970       981   +11     
  Branches       127       130    +3     
=========================================
+ Hits           970       981   +11     

Impacted Files	Coverage Δ
vault_cli/cli.py	100.00% <100.00%> (ø)

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[ewjoachim]

Thanks @sheb

Only thing left seems:

./vault_cli/cli.py:2:1: F401 'json' imported but unused
./tests/unit/test_cli.py:463:36: F541 f-string is missing placeholders

[ewjoachim]

Meanwhile: a mypy update has broken the build :D

Your choice: we can solve this in this PR or in a new PR, it's independant from the modification this PR did bring. I have limited time to take care of this now, but I'll review anything you ping me on :)