Update docs about Require section
Update docs about Require section

Include example with no version information.
Include information, that version is optional in Require dict.

Change-Id: I476e4fcbe4812d766d81c5ff4787a42bdd6637a3

DavidPurcell/murano_temp,chenyujie/hybrid-murano,sajuptpm/murano,satish-avninetworks/murano,NeCTAR-RC/murano,NeCTAR-RC/murano,NeCTAR-RC/murano,olivierlemasle/murano,openstack/murano,olivierlemasle/murano,DavidPurcell/murano_temp,NeCTAR-RC/murano,olivierlemasle/murano,satish-avninetworks/murano,openstack/murano,chenyujie/hybrid-murano,olivierlemasle/murano,sajuptpm/murano,satish-avninetworks/murano,DavidPurcell/murano_temp,satish-avninetworks/murano,DavidPurcell/murano_temp