Sync an out of date branch of a fork from the web

You can now use the web UI to synchronize an out of date branch of a fork with its upstream branch. If there are no merge conflicts between the branches, the fork's branch is updated either by fast-forwarding or by merging from the upstream's branch. If there are conflicts, you will be prompted to open a pull request to resolve.

Fetch upstream up to date, no conflict, and conflict flows