CI for checking pixi env on RTFD will succeed (Open-MSS#3002)

Author: ReimarBauer

.github/workflows/readthedocs_basics.yml

@@ -0,0 +1,19 @@
+name: RTFD env basics
+
+on:
+  pull_request:
+
+jobs:
+  Test-RTFD:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v4
+    - uses: prefix-dev/setup-pixi@a0af7a228712d6121d37aba47adf55c1332c9c2e # v0.9.4
+      with:
+        pixi-version: latest
+        cache: true
+        environments: docs
+    - name: try sphinx build
+      timeout-minutes: 20
+      run: |
+        pixi run -e docs sphinx-build -T -b html docs docs/html

.readthedocs.yaml

@@ -1,12 +1,17 @@
 version: 2
 
 build:
-  os: "ubuntu-22.04"
-  tools:
-    python: "mambaforge-4.10"
-
-sphinx:
-  configuration: docs/conf.py
-
-conda:
-  environment: docs/environment.yml
+   os: ubuntu-24.04
+   tools:
+       python: "latest"
+   jobs:
+      create_environment:
+         - asdf plugin add pixi
+         - asdf install pixi latest
+         - asdf global pixi latest
+      install:
+         # assuming you have an environment called "docs"
+         - pixi install -e docs
+      build:
+         html:
+            - pixi run -e docs sphinx-build -T -b html docs $READTHEDOCS_OUTPUT/html