docs(changelog) update unreleased for 0.3.0
docs(changelog) update unreleased for 0.3.0

bbalu/kong,ChristopherBiscardi/kong,peterayeni/kong,skynet/kong,sbuettner/kong,Skyscanner/kong,puug/kong,paritoshmmmec/kong,AnsonSmith/kong,vmercierfr/kong,chourobin/kong,wakermahmud/kong