devel/py-pytest-cpp: Add py-pytest-cpp 2.3.0

pytest-cpp uses pytest runner to discover and execute C++ tests. It supports
Google Test, Boost.Test, and Catch2.

This brings several benefits:

• Allows you to run all your tests in multi-language projects with a single command;
• Execute C++ tests in parallel using pytest-xdist plugin;
• Use --junitxml option to produce a single and uniform xml file with all your test suite results;
• Filter which tests to run using standard test filtering capabilities, such as by file names, directories, keywords by using the -k option, etc.;