bench_run.yaml disable write to cache (still reads from cache) (#906)

.github/workflows/bench_run.yaml

@@ -25,10 +25,7 @@ jobs:
         # This workflow does not run on main, so to make use of a cache before this workflow has completed once on a PR,
         # we need to manually recreate the key used by ubuntu-20.04 release builds.
         shared-key: "ubuntu-20.04 - --release-build_and_test"
-        # TODO: while we want to leach off this cache we dont want to overwrite it
-        #       so once something like https://github.com/Swatinem/rust-cache/issues/66 becomes available,
-        #       we should do something like this:
-        # save-if: false
+        save-if: false
     - name: cache custom ubuntu packages
       uses: actions/cache@v3
       with: