Updates to deprecated commands

[jdebacker]

This PR fixed some errors arising from deprecated packages (namely, pkg_resources) and methods (e.g., the behavior of the replace method on Pandas DataFrames.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.91%. Comparing base (69cdc1a) to head (a917b80).
Report is 10 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##            master     #396      +/-   ##
===========================================
- Coverage   100.00%   99.91%   -0.09%     
===========================================
  Files           11       11              
  Lines         1140     1140              
===========================================
- Hits          1140     1139       -1     
- Misses           0        1       +1     

Flag	Coverage Δ
unittests	99.91% <100.00%> (-0.09%)	⬇️

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Files with missing lines	Coverage Δ
ccc/__init__.py	100.00% <100.00%> (ø)
ccc/calcfunctions.py	100.00% <100.00%> (ø)
ccc/calculator.py	100.00% <ø> (ø)
ccc/constants.py	100.00% <ø> (ø)
ccc/parameters.py	100.00% <100.00%> (ø)
ccc/utils.py	98.97% <100.00%> (-1.03%)	⬇️