git: clarify CI flags in PR template
git: clarify CI flags in PR template

The commitlint bot is rarely understood and flags to skip the CI are
rarely used by new contributors. This update to the PR template
aims to make these options more discoverable to newer members of
the community

Signed-off-by: Travis Nielsen <a8b474fdb3f77f44446f0ab9ddca8147b09b3a9e@redhat.com>

rook/rook,rook/nfs,rook/rook,rook/rook,rook/nfs,rook/rook,rook/rook,rook/nfs