Updated Matrix address, and added links to libmegapixels, libdng and postprocessd

README.md

@@ -3,11 +3,11 @@
 A GTK4 camera application that knows how to deal with the media request api. It uses
 opengl to debayer the raw sensor data for the preview.
 
-chat: #megapixels:postmarketos.org on matrix
+Chat: [#megapixels:brixit.nl](https://matrix.to/#/#megapixels:brixit.nl) on Matrix
 
 ## Building
 
-Before building this, build and install libmegapixels, libdng and postprocessd.
+Before building this, build and install [libmegapixels](https://gitlab.com/megapixels-org/libmegapixels), [libdng](https://gitlab.com/megapixels-org/libdng) and [postprocessd](https://gitlab.com/megapixels-org/postprocessd).
 
 ```shell-session
 $ meson build