Revert "Remove DCO sign-off and test checks"
Revert "Remove DCO sign-off and test checks"

This reverts commit 07d49ac103943b80f5ceaf32c78146bee8992829.

dita-ot/dita-ot,shaneataylor/dita-ot,infotexture/dita-ot,infotexture/dita-ot,shaneataylor/dita-ot,dita-ot/dita-ot,infotexture/dita-ot,drmacro/dita-ot,infotexture/dita-ot,shaneataylor/dita-ot,dita-ot/dita-ot,drmacro/dita-ot,dita-ot/dita-ot,shaneataylor/dita-ot,shaneataylor/dita-ot,drmacro/dita-ot,drmacro/dita-ot,drmacro/dita-ot,dita-ot/dita-ot,infotexture/dita-ot