ci(backend test): add working directory

.github/workflows/backend-test.yaml

@@ -1,4 +1,4 @@
-name: backend Test
+name: Backend Test
 
 on:
   push:
@@ -17,6 +17,8 @@ jobs:
       - name: Install Poetry
         uses: snok/install-poetry@v1 
       - name: Install Deps
+        working-directory: ./backend/app
         run: poetry install --with dev
       - name: Run Tests
+        working-directory: ./backend/app
         run: pytest