Jira DVCS import log includes error "API V3 is no longer supported. Use API V4 instead" when user information is requested

Summary

Noticed some "API V3 is no longer supported. Use API V4 instead" entries in Jira Logs when DVCS soft sync was executed while testing the implementation within !10342 (merged) . Turns out there is an endpoint missing for Jira to request user information.

What is the current bug behavior?

Jira seems to run into exceptions when retrieving user information during soft sync a DVCS account.

What is the expected correct behavior?

Jira DVCS import runs without exceptions in error log when user information is requested.

Relevant logs and/or screenshots

[c.a.j.p.dvcs.service.RepositoryServiceImpl] Could not load user [someuser42, someuser42] - java.lang.RuntimeException: org.eclipse.egit.github.core.client.RequestException: API V3 is no longer supported. Use API V4 instead. (410)

Possible fixes

Implement missing endpoint (@pderichs already started to work on that).