Support python 3.12 & minor improvements

[qqaatw]

Summary:

1. Support Python 3.12.
2. Use context manager for lock.
3. Add more tests.
4. Update docs.

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (dbe4bbe) 92.18% compared to head (ef29eca) 92.41%.

Files	Patch %	Lines
JciHitachi/aws_connection.py	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #10      +/-   ##
==========================================
+ Coverage   92.18%   92.41%   +0.23%     
==========================================
  Files           8        8              
  Lines         793      791       -2     
==========================================
  Hits          731      731              
+ Misses         62       60       -2     

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