Upgrade actions/cache from v2 to v3

Author: geofranzi

.github/workflows/main.yml

@@ -20,7 +20,7 @@ jobs:
           node-version: '16'
 
       - name: Cache pnpm modules
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: ~/.pnpm-store
           key: ${{ runner.os }}-${{ hashFiles('**/pnpm-lock.yaml') }}