vagrant: Add minimum vagrant version requirement.
vagrant: Add minimum vagrant version requirement.

Also, clarify the directory that you should start with.

Signed-off-by: Gurucharan Shetty <a1872e333d0e52644f6125da2276530f7ebe5e77@ovn.org>

shettyg/ovn-kubernetes,shettyg/ovn-kubernetes,shettyg/ovn-kubernetes