Add cache & test

.github/workflows/github-actions-demo.yml

@@ -7,6 +7,17 @@ jobs:
     steps:
       - name: Check out repository code
         uses: actions/checkout@v4
+
+      - name: Mount bazel cache
+        uses: actions/cache@v3
+        with:
+          path: "/home/runner/.cache/bazel"
+          key: bazel
+
       - name: bazel build
         run: |
           bazel build ...
+
+      - name: bazel test
+        run: |
+          bazel test ...