Add URL to old PDF docs & clean up github workflows

.github/workflows/main.yml

@@ -68,16 +68,17 @@ jobs:
             test-suite/tests/test*/test.out*
 
   docs:
-    name: Build docs
+    name: Validate mkdocs links
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.11"
+          # use the latest stable version
+          python-version: "3.x"
           cache: "pip"
       - run: pip install -r docs/requirements.txt
-      - run: mkdocs build -s
+      - run: mkdocs build --strict
         working-directory: ./docs
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.readthedocs.yaml

@@ -1,19 +1,17 @@
 # Read the Docs configuration file for MkDocs projects
 # See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
 
-# Required
 version: 2
 
-# Set the version of Python and other tools you might need
 build:
   os: ubuntu-22.04
   tools:
-    python: "3.12"
+    # latest 3.x version available on Read the Docs
+    python: "3"
 
 mkdocs:
   configuration: docs/mkdocs.yml
 
-# Optionally declare the Python requirements required to build your docs
 python:
   install:
   - requirements: docs/requirements.txt

docs/docs/index.md

@@ -18,3 +18,6 @@ This documentation contains the following sections:
 
 - [User guide](user_guide/introduction.md)
 - [Tutorials](tutorials/preliminaries.md)
+
+For historical reference, the old latex PDF documentation of Wannier90 v3.1
+can be found on the [Wannier90 website](https://wannier.org/support/).