Install yarn in the workflow

.gitea/workflows/build.yaml

@@ -17,6 +17,8 @@ jobs:
           node-version: '20.x'
       - name: Install dependencies
         run: npm install
+      - name: Install yarn
+        run: npm install --global yarn
       - name: Install Quasar CLI
         run: npm install -g @quasar/cli
       - name: Build Project