chore(deps): update actions/cache action to v3 (#17)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
         uses: cashapp/activate-hermit@v1
 
       - name: Cache Flutter
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: ~/.cache/hermit/cache/pkg
           key: ${{ runner.os }}-hermit-cache-${{ hashFiles('bin/.*.pkg') }}