Fix website workflow (#339)

Author: seanzhangkx8

.github/workflows/website.yml

@@ -9,15 +9,14 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
+    - uses: actions/setup-python@v5
+      with:
+        python-version: "3.12"
     - name: Install Dependencies
-      run: |
-        pip install sphinx shibuya m2r2
+      run: pip install -r website/docs/requirements.txt
     - name: Sphinx Build
-      uses: ammaraskar/sphinx-action@master
-      with:
-        docs-folder: "website/docs/"
-        build-command: "sphinx-build -b html ./source ./build"
+      run: cd website/docs && sphinx-build -b html ./source ./build
     - name: rsync homepage files
       uses: burnett01/rsync-deployments@master
       with:

website/docs/requirements.txt

@@ -1,3 +1,6 @@
-sphinx
+# Pin Sphinx and docutils so CI image upgrades from default 2.4.4/0.16.
+# Shibuya theme requires document.findall() (docutils >= 0.18). m2r2 needs docutils >= 0.19.
+sphinx>=5.0
+docutils>=0.19
 shibuya
 m2r2