👷 update ci add cache

.github/workflows/build_docs.yml

@@ -19,10 +19,17 @@ jobs:
           python-version: 3.8
           architecture: "x64"
 
-      - name: Install Dependences
+      - uses: Gr1N/setup-poetry@v4
+
+      - uses: actions/cache@v1
+        with:
+          path: ~/.cache/pypoetry/virtualenvs
+          key: ${{ runner.os }}-poetry-${{ hashFiles('poetry.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-poetry-
+
+      - name: Set up dependencies
         run: |
-          python -m pip install --upgrade pip
-          pip install poetry
           poetry install
 
       - name: Build Doc