JavaDocs CI failing

[goneall]

When performing a release, the JavaDocs CI fails with the following error:

/usr/bin/git push origin gh-pages
  To https://github.com/spdx/spdx-java-v3jsonld-store.git
   ! [remote rejected] gh-pages -> gh-pages (cannot lock ref 'refs/heads/gh-pages': is at 41bbb0561a481417b3cb46f34cd755aa62c0d320 but expected f1458988b70b98e09505411beaa451ec4481904e)
  error: failed to push some refs to 'https://github.com/spdx/spdx-java-v3jsonld-store.git'

If the job is re-run, it tends to succeed.

Possibly a race condition with the another CI action?

[bact]

I found GitHub CI today is flaky. Some jobs need to wait in a queue (less than 5 mins, but they were usually instant).