chore: update GitHub Actions workflow to use Yarn for dependency management and build process

Author: danieldanielecki

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

@@ -11,7 +11,14 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - run: npm ci && npm run build
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: yarn
+      - name: Install dependencies
+        run: yarn install --frozen-lockfile
+      - name: Build
+        run: yarn build
       - uses: FirebaseExtended/action-hosting-deploy@v0
         with:
           repoToken: ${{ secrets.GITHUB_TOKEN }}