[doc] contributing: Add § to suggest to read used modules docs

CONTRIBUTING.md

@@ -35,6 +35,15 @@ Use DuniterPy as a [path dependency](https://python-poetry.org/docs/versions/#pa
 poetry add ../duniterpy
 ```
 
+### Developing with modules
+Silkaj is using Python modules which shape kind of a framework.
+Please read their documentations on how to use them the best possible.
+- [DuniterPy](https://clients.duniter.io/python/duniterpy/index.html): Autogenerated documentation.
+  - Feel free to contribute upstream to share the code with other Python programs
+- [Click](https://click.palletsprojects.com/#documentation)
+- [Pendulum](https://pendulum.eustace.io/docs/)
+- [texttable](https://github.com/foutaise/texttable/#documentation)
+
 ## Formatting
 We are using [Black](https://github.com/python/black) formatter tool.
 To have Black installed in your Poetry virtualenv, you will need Python v3.6 or greater.
@@ -112,7 +121,7 @@ The `--extra-index-url` is used to retrieve dependencies packages from the offic
   - Build
 - Tests on supported Python versions:
   - Installation
-  - Pytest for v3.6, 3.7, and 3.8
+  - Pytest on Python supported versions
 - PyPI distribution
   - test
   - stable