adopt latest version of myst-to-pages.yml

Author: parmentelat

.github/workflows/myst-to-pages.yml

@@ -43,11 +43,11 @@ jobs:
         uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 22
+          node-version: 24
       - name: Install MyST Markdown
         run: npm install -g mystmd
       - name: Install requirements.txt
-        run: pip install -r requirements.txt
+        run: "if [ -f requirements.txt ]; then pip install -r requirements.txt; fi"
       - name: Setup Graphviz
         uses: ts-graphviz/setup-graphviz@v2
       - name: Build HTML Assets