I just upgraded to Jenkins 2.32.2 and then to GitHub Branch Source 2.0.1 when prompted, but now it's refusing to load due to a dependency on SCM API 2.0.2 or later. However, the latest version of SCM API on the LTS branch appears to be 1.3 – that's what I have, and no newer version is listed in the Manage Plugins page.

EDIT: I originally filed this under the scm-api-plugin component but have added github-branch-source-plugin component since the issue relates to both.