Use `log --author=bors` instead of `merge-base`
Use `log --author=bors` instead of `merge-base`

aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust