chore: add resource under python:python-testing:pytest

src/data/roadmaps/python/content/107-python-testing/101-pytest.md

@@ -6,3 +6,4 @@ Visit the following resources to learn more:
 
 - [Official Docs](https://docs.pytest.org/)
 - [Pytest Tutorial](https://www.tutorialspoint.com/pytest/index.htm)
+- [Effective Python Testing With Pytest](https://realpython.com/pytest-python-testing/)