docs: fix build process for sphinx

.readthedocs.yaml

@@ -7,9 +7,9 @@ version: 2
 
 # Set the version of Python and other tools you might need
 build:
-  os: ubuntu-20.04
+  os: ubuntu-22.04
   tools:
-    python: "3.10"
+    python: "3.11"
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
@@ -23,3 +23,5 @@ sphinx:
 python:
   install:
     - requirements: docs/requirements.txt
+    - method: pip
+      path: .[dev]

docs/requirements.txt

@@ -7,6 +7,4 @@ sphinx-copybutton
 sphinx-inline-tabs
 myst-parser
 sphinx-design
-PySide6~=6.8.2
-bec-widgets
 tomli