docs: remove the CLA agreement from CONTRIBUTING.md
docs: remove the CLA agreement from CONTRIBUTING.md

ejoncas/kong,salazar/kong,ajayk/kong,beauli/kong,xvaara/kong,icyxp/kong,jerizm/kong,ccyphers/kong,smanolache/kong,rafael/kong,li-wl/kong,vzaramel/kong,isdom/kong,streamdataio/kong,jebenexer/kong,streamdataio/kong,ind9/kong,Vermeille/kong,Kong/kong,ind9/kong,Mashape/kong,ejoncas/kong,isdom/kong,rafael/kong,kyroskoh/kong,shiprabehera/kong,vzaramel/kong,Kong/kong,akh00/kong,kyroskoh/kong,Kong/kong