chore: 깃헙 엑션 오류 수정

.github/workflows/test-backend-app.yaml

@@ -33,9 +33,8 @@ jobs:
       - uses: actions/cache@v3
         name: Define a cache for the virtual environment based on the dependencies lock file
         with:
-          path: ./.venv
+          path: ${{env.working-directory}}/.venv
           key: venv-${{ hashFiles('poetry.lock') }}
-        working-directory: ${{env.working-directory}}
 
       - name: install the project dependencies
         run: poetry install