Revert "debug: v2 doesnt have separate save/restore actions"

This reverts commit fd5020c6d8.

.github/workflows/main.yml

@@ -17,7 +17,7 @@ jobs:
             -   run: npm run build --if-present
             -   name: Cache build
                 id: cache
-                uses: actions/cache@v2
+                uses: actions/cache/save@v2
                 with:
                     # npm cache files are stored in `~/.npm` on Linux/macOS
                     path: ./
@@ -26,7 +26,7 @@ jobs:
         runs-on: ubuntu-latest
         needs: build
         steps:
-            -  uses: actions/cache@v2
+            -  uses: actions/cache/restore@v2
                with:
                    path: .
                    key: cache-${{ github.run_id }}-${{ github.run_attempt }}