Update .readthedocs.yaml

.readthedocs.yaml

@@ -7,24 +7,12 @@ version: 2
 
 build:
   os: ubuntu-22.04
-  apt_packages:
-    - mpich
-    - libfftw3-dev
   tools:
-    python: "mambaforge-22.9"
-  jobs:
-    post_create_environment:
-      - python -m pip install sphinx_rtd_theme
-      - python -m pip install reframe-hpc
-
-conda:
-  environment: conda_env.yml
+    python: "3.9"
 
 python:
   install:
     - requirements: docs/requirements.txt
-    - method: setuptools
-      path: .
 
 sphinx:
    configuration: docs/source/conf.py