Fix dictconfig resetting child loggers

[aminalaee]

Fixes #67 .

The code was using the CPython version with PlaceHolder, it didn't have test coverage. This adds the tests and fixes the issue.

[codecov-commenter]

Codecov Report

Merging #70 (8e0f3e5) into main (16f49d3) will increase coverage by 0.46%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #70      +/-   ##
==========================================
+ Coverage   85.55%   86.01%   +0.46%     
==========================================
  Files          11       11              
  Lines        2125     2124       -1     
==========================================
+ Hits         1818     1827       +9     
+ Misses        307      297      -10     

Impacted Files	Coverage Δ
src/picologging/__init__.py	92.69% <ø> (ø)
src/picologging/config.py	82.38% <100.00%> (+4.65%)	⬆️

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[tonybaloney]

Thanks @aminalaee I'll raise another issue to improve the coverage of the config submodule as well