Try to install myst with pip

Author: finsberg

.github/workflows/build_docs.yml

@@ -23,11 +23,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
         with:
-          node-version: 18.x
+          python-version: '3.11'
+
       - name: Install MyST
-        run: npm install -g mystmd
+        run: python3 -m pip install mystmd
+
       - name: Build HTML Assets
         run: myst build --strict --ci --html