Cache deploy files

Author: rowanc1

.github/workflows/deploy.yml

@@ -32,6 +32,11 @@ jobs:
       - uses: actions/checkout@v4
       - name: Setup Pages
         uses: actions/configure-pages@v3
+      - name: Cache Notebook Execution
+        uses: actions/cache@v3
+        with:
+          path: ./lectures/_build/execute
+          key: ${{ runner.os }}-execute-cache-${{ hashFiles('lectures/**/*.md') }}
       - uses: actions/setup-node@v4
         with:
           node-version: 18.x