Add missing requirement to docs/requirements.txt (#329)

docs/conf.py

@@ -43,6 +43,7 @@ extensions = [
     "sphinx.ext.autodoc",
     "sphinx.ext.githubpages",
     "myst_parser",
+    "sphinx_github_changelog",
 ]
 
 source_suffix = {

docs/requirements.txt

@@ -3,4 +3,5 @@ sphinx-notfound-page
 myst-parser
 git+https://github.com/Farama-Foundation/Celshast#egg=furo
 moviepy
-pygame
+pygame
+sphinx_github_changelog