[ticket/11674] Do not include vendor folder if there are no dependencies.

PHPBB3-11674
Merge remote-tracking branch 'github-bantu/ticket/11674' into prep-release-3.0.12

* github-bantu/ticket/11674:
  [ticket/11674] Do not include vendor folder if there are no dependencies.
Merge branch 'prep-release-3.0.12' into develop-olympus

* prep-release-3.0.12:
  [ticket/11674] Do not include vendor folder if there are no dependencies.