fix readthedocs dependencies installation (#63)

* fix readthedocs dependencies installation

* add apt_packages

.readthedocs.yaml

@@ -10,13 +10,24 @@ build:
   os: ubuntu-22.04
   tools:
     python: "3.11"
+  apt_packages:
+    - graphviz
+    - libsdl2-dev
+    - libsdl2-image-dev
+    - libsdl2-ttf-dev
+    - libfreetype6-dev
+    - libjpeg-dev
+    - python3-dev
+    - python3-numpy
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
   configuration: doc/conf.py
 
-# We recommend specifying your dependencies to enable reproducible builds:
-# https://docs.readthedocs.io/en/stable/guides/reproducible-builds.html
+# Install dependencies
 python:
   install:
-    - requirements: docs
+    - method: pip
+      path: .
+      extra_requirements:
+        - docs