docs: add Matrix room

Author: Deuchnord

README.md

@@ -1,5 +1,6 @@
 # ![Kosmorro](https://github.com/Kosmorro/logos/raw/main/kosmorro/kosmorro-artwork.jpg)
-[![Version on PyPI](https://img.shields.io/pypi/v/kosmorro)](https://pypi.org/project/kosmorro) [![Packaging status](https://repology.org/badge/tiny-repos/kosmorro.svg)](https://repology.org/project/kosmorro/versions) [![Help translating Kosmorro!](https://hosted.weblate.org/widgets/kosmorro/-/cli/svg-badge.svg)](https://hosted.weblate.org/engage/kosmorro/)
+[![Version on PyPI](https://img.shields.io/pypi/v/kosmorro)](https://pypi.org/project/kosmorro) [![Packaging status](https://repology.org/badge/tiny-repos/kosmorro.svg)](https://repology.org/project/kosmorro/versions) [![Help translating Kosmorro!](https://hosted.weblate.org/widgets/kosmorro/-/cli/svg-badge.svg)](https://hosted.weblate.org/engage/kosmorro/) [![Matrix](https://img.shields.io/matrix/kosmorro-cli%3Amatrix.org?logo=matrix)
+](https://matrix.to/#/#kosmorro-cli:matrix.org)
 
 Kosmorro is a program that calculates your astronomical ephemerides.