doc: Adding contributing and contact information to the main page

Author: mgm8

docs/index.rst

@@ -9,6 +9,10 @@ PyNGHam Library Documentation
 
 The PyNGHam library is a Python version of the original NGHam protocol library written in C by Jon Petter Skagmo (LA3JPA).
 
+The project is fully open source and is available in a `GitHub repository <https://github.com/mgm8/pyngham>`_. All contributions are welcome! If you found a bug, developed a new feature, or want to improve the documentation, there are two ways to do so: open an issue describing the suggested modification, or by opening a pull request. More information are available in the `CONTRIBUTING file <https://github.com/mgm8/pyngham/blob/main/CONTRIBUTING.md>`_.
+
+Any questions or suggestions can also be addressed to Gabriel Mariano Marcelino <`[email protected] `<mailto:[email protected]>`_>.
+
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