Update README.md (#373)

'did ran' or 'last ran' isn't correct.

README.md

@@ -26,7 +26,7 @@ their
 [semi-linear history and fast-forward](https://docs.gitlab.com/ee/user/project/merge_requests/) merge
 request methods: in both cases a merge request can only be accepted if the
 resulting master branch will be effectively the same as the merge request branch
-on which CI has passed. If master has changed since the tests were last ran, it
+on which CI has passed. If master has changed since the tests were last run, it
 is the *user's responsibility* to rebase the changes and retry. But this just
 doesn't scale: if you have, a mono-repo, a large team working on short-lived
 branches, a CI pipeline that takes 5-10 minutes to complete... then the number