Simplify docs conf

Signed-off-by: Bernát Gábor <gaborjbernat@gmail.com>

Author: gaborbernat

.readthedocs.yml

@@ -1,18 +1,15 @@
 version: 2
 build:
-  os: ubuntu-20.04
+  os: ubuntu-22.04
   tools:
-    python: "3.10"
-formats:
-  - htmlzip
-  - epub
-  - pdf
+    python: "3"
 python:
-   install:
-      - method: pip
-        path: .
-        extra_requirements: ["docs"]
+  install:
+    - method: pip
+      path: .
+      extra_requirements:
+        - docs
 sphinx:
   builder: html
   configuration: docs/conf.py
-  fail_on_warning: false
+  fail_on_warning: true