docs: add .readthedocs.yml

Fix the readthedocs config.

.readthedocs.yml

@@ -0,0 +1,21 @@
+# .readthedocs.yml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "3.8"
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  configuration: docs/conf.py
+
+python:
+  install:
+  - requirements: "requirements/docs.txt"
+  - method: pip
+    path: .