test: Added unittests with Alert API

[frgfm]

This PR introduces the following modifications:

• updates test dependencies
• passes down .env from the CI
• adds unittests with the API
• improves logging in Engine
• renames client_creds into cam_creds
• fixes edge case for state update
• return HTTP response in private methods (for unittests)

Closes #51

Any feedback is welcome!

[codecov]

Codecov Report

Merging #108 (c6b6903) into main (731391c) will increase coverage by 27.25%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##             main     #108       +/-   ##
===========================================
+ Coverage   67.90%   95.15%   +27.25%     
===========================================
  Files           3        3               
  Lines         162      165        +3     
===========================================
+ Hits          110      157       +47     
+ Misses         52        8       -44     

Flag	Coverage Δ
unittests	95.15% <100.00%> (+27.25%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pyroengine/core.py	94.20% <100.00%> (+32.72%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[frgfm]

All good, and now we got 94% of coverage 😁