EIP bot should merge asset changes

If the author of EIP-N makes a change the assets in EIP-N, the EIP bot should be able to understand this and merge it. It seems though in PRs like https://github.com/ethereum/ERCs/pull/1289 and https://github.com/ethereum/ERCs/pull/1325. In the second, it actually tags editors to review.