Update URL to pango in README.md (#2334)

https://pango.gnome.org gets `ERR_NAME_NOT_RESOLVED`

Author: refack

README.md

@@ -24,7 +24,7 @@ Note, there are two versions of manim.  This repository began as a personal proj
 Manim runs on Python 3.7 or higher.
 
 System requirements are [FFmpeg](https://ffmpeg.org/), [OpenGL](https://www.opengl.org/) and [LaTeX](https://www.latex-project.org) (optional, if you want to use LaTeX).
-For Linux, [Pango](https://pango.gnome.org) along with its development headers are required. See instruction [here](https://github.com/ManimCommunity/ManimPango#building).
+For Linux, [Pango](https://pango.org) along with its development headers are required. See instruction [here](https://github.com/ManimCommunity/ManimPango#building).
 
 
 ### Directly