Update git submodules

* Update helpcontent2 from branch 'master'
  - Help files: http -> https
    
    + some more conservative changes
    
    Change-Id: I806fc7998e96cc43f6db35d9f3d13f247960abc0
    Reviewed-on: https://gerrit.libreoffice.org/63199
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 3984e2ba

-Subproject commit f9be6d3f75aeb98826fd0fda6f5807f0e7118d36
+Subproject commit 3984e2baefed611f79a36b85f3884a8cc2779653