Add a Matrix Strategy to GitHub Actions for Testing BlueMath on Multiple OS and Python Versions

[fernanqv]

To verify that BlueMath works on multiple Python versions across different operating systems, a matrix with various OS and Python versions should be added to the GitHub Actions workflow python-tests.yml

Something similar to what is explained in this link:
https://www.geeksforgeeks.org/the-matrix-strategy-in-github-actions/

[tausiaj]

Closed issue in #42