docs: add CONTRIBUTING.md file (#285)

Co-authored-by: Roberto Pastor Muela <37798125+RobPasMue@users.noreply.github.com>

CONTRIBUTING.md

@@ -0,0 +1,10 @@
+# Contributing
+
+If you are interested in contributing to our project, please make sure to review
+our contribution guidelines, which are specified in the
+[PyAnsys Developer's Documentation - Contributing](https://dev.docs.pyansys.com/how-to/contributing.html) page. This document
+outlines the process for submitting issues, proposing changes, and making pull
+requests to our codebase. Following these guidelines will help ensure that your
+contributions are properly integrated and reviewed, and will help maintain the
+overall quality and consistency of the project. Thank you for your interest in
+contributing to our community.

README.rst

@@ -26,6 +26,10 @@ Ansys Sphinx theme
    :target: https://github.com/psf/black
    :alt: Black
 
+.. |Downloads| image:: https://img.shields.io/pypi/dm/ansys-sphinx-theme.svg?label=PyPI%20downloads
+   :target: https://pypi.org/project/ansys-sphinx-theme
+   :alt: Downloads
+
 
 Introduction
 ------------