Configure installing dependencies with npm

.github/workflows/firebase-hosting-merge.yml

@@ -12,6 +12,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - name: Install npm dependencies
+        working-directory: ./client
+        run: npm install
       - name: Build Svelte app
         working-directory: ./client
         run: npm run build

.github/workflows/firebase-hosting-pull-request.yml

@@ -9,6 +9,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - name: Install npm dependencies
+        working-directory: ./client
+        run: npm install
       - name: Build Svelte app
         working-directory: ./client
         run: npm run build