Use HTTPS instead of Git protocol for submodules
Use HTTPS instead of Git protocol for submodules

Ref https://help.github.com/articles/page-build-failed-invalid-submodule/
drmacro/dita-ot,shaneataylor/dita-ot,shaneataylor/dita-ot,robander/dita-ot,shaneataylor/dita-ot,infotexture/dita-ot,robander/dita-ot,robander/dita-ot,dita-ot/dita-ot,dita-ot/dita-ot,dita-ot/dita-ot,shaneataylor/dita-ot,infotexture/dita-ot,robander/dita-ot,robander/dita-ot,dita-ot/dita-ot,dita-ot/dita-ot,infotexture/dita-ot,drmacro/dita-ot,drmacro/dita-ot,drmacro/dita-ot,infotexture/dita-ot,infotexture/dita-ot,shaneataylor/dita-ot,drmacro/dita-ot