Add support for Cloud Functions for Firebase (#444)

Author: jhuleatt

.github/workflows/test.yaml

@@ -93,6 +93,9 @@ jobs:
         run: |
           yarn config set yarn-offline-mirror ~/.npm-packages-offline-cache
           yarn install --frozen-lockfile --prefer-offline
+      - name: Install deps for functions
+        run: npm install
+        working-directory: ./functions
       - name: Firebase emulator cache
         uses: actions/cache@v2
         with: