ci: add dependency cache (#6199)

.github/workflows/deploy-docs.yml

@@ -26,6 +26,18 @@ jobs:
         with:
           version: latest
 
+      - name: Cache ~/.pnpm-store
+        uses: actions/cache@v2
+        env:
+          cache-name: cache-pnpm-store
+        with:
+          path: ~/.pnpm-store
+          key: ${{ runner.os }}-publish-${{ env.cache-name }}-${{ hashFiles('**/pnpm-lock.yaml') }}
+          restore-keys: |
+            ${{ runner.os }}-publish-${{ env.cache-name }}-
+            ${{ runner.os }}-publish-
+            ${{ runner.os }}-
+
       - name: Install dependencies
         run: pnpm i --frozen-lockfile