Check run-tests.yml actions/cache::restore-keys instead of keys

With `actions/cache@v2` the `keys` config got renamed to `resore-keys` we should ensure that this new config key is used in all actions instead of the outdated one.

Start by opening run-tests.yml and inspect its actions/cache@v2 configuration, checking the cache key fields against the issue description. Update the outdated field to the intended restore-keys configuration and verify that all relevant actions in the file use the current name.

Written by the indexing model from the issue text.