Update release process docs for 1.2
Update release process docs for 1.2

pjedrzejewski/Sylius,GSadee/Sylius,diimpp/Sylius,Arminek/Sylius,foobarflies/Sylius,101medialab/Sylius,lchrusciel/Sylius,mbabker/Sylius,Zales0123/Sylius,pjedrzejewski/Sylius,foobarflies/Sylius,Sylius/Sylius,GSadee/Sylius,mbabker/Sylius,diimpp/Sylius,foobarflies/Sylius,SyliusBot/Sylius,Sylius/Sylius,pjedrzejewski/Sylius,Zales0123/Sylius,SyliusBot/Sylius,antonioperic/Sylius,pamil/Sylius,101medialab/Sylius,loic425/Sylius,Zales0123/Sylius,antonioperic/Sylius,antonioperic/Sylius,kayue/Sylius,kayue/Sylius,diimpp/Sylius,101medialab/Sylius,lchrusciel/Sylius,mbabker/Sylius,Arminek/Sylius,foobarflies/Sylius,mbabker/Sylius,Sylius/Sylius,loic425/Sylius,pamil/Sylius,loic425/Sylius,pamil/Sylius,kayue/Sylius,pjedrzejewski/Sylius,SyliusBot/Sylius,lchrusciel/Sylius,GSadee/Sylius,Arminek/Sylius