ci: use cashapp/activate-hermit native caching

.github/workflows/ci.yml

@@ -15,20 +15,8 @@ jobs:
 
       - name: Init Hermit
         uses: cashapp/activate-hermit@v1
-
-      - name: Folder Hash
-        id: bin-hash
-        uses: theowenyoung/folder-hash@v3
-        with:
-          path: bin
-
-      - name: Cache Flutter
-        uses: actions/cache@v3
         with:
-          path: ~/.cache/hermit/pkg
-          key: ${{ runner.os }}-hermit-cache-${{ steps.bin-hash.outputs.hash }}
-          restore-keys: |
-            ${{ runner.os }}-hermit-cache-
+          cache: true
 
       - name: Install Dependencies
         run: |