refactor: use pathlib.Path for file paths

[uniqueg]

Description

• use pathlib.Path for passing file paths and replacing operations from the os module
• bump version to v0.9.0

Type of change

Please delete options that are not relevant.

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation update

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have updated the documentation (or documentation does not need to be updated)
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] I have not reduced the existing code coverage

[codecov[bot]]

Codecov Report

Merging #134 (c6108e2) into dev (54c6929) will not change coverage. The diff coverage is 100.00%.

@@            Coverage Diff            @@
##               dev      #134   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           14        14           
  Lines          694       695    +1     
=========================================
+ Hits           694       695    +1     

Impacted Files	Coverage Δ
foca/__init__.py	100.00% <100.00%> (ø)
foca/config/config_parser.py	100.00% <100.00%> (ø)
foca/foca.py	100.00% <100.00%> (ø)
foca/models/config.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 54c6929...c6108e2. Read the comment docs.