If your PR already has a cache and you want to keep doing development with the old version of `riscv-tools`, no action is needed.
If you want to merge or rebase your PR on top of `master` with the new version of `riscv-tools`, you should delete your PR branch's local cache. Otherwise it will rebuild the branch cache instead of using `master`'s cache. To do this:
1. Wait for the previous steps to go through so that the `master` cache is done.
2. On Travis, click `More Options -> Caches` on the upper right.
3. Click `Delete` for your PR branch's cache.
4. Push updates to the PR as usual, it should download the new `master` cache.