Update git submodules

* Update helpcontent2 from branch 'master'
  - Help files: http -> https
    
    + some more conservative changes
    
    Change-Id: I204669f4deb01cdb2ebdd22398f52779d3501053
    Reviewed-on: https://gerrit.libreoffice.org/63220
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ f9be6d3f

-Subproject commit f2055896d9bd94736ce5b38a3e769c41d9fab0f9
+Subproject commit f9be6d3f75aeb98826fd0fda6f5807f0e7118d36