update changelog for 0.7
update changelog for 0.7

leasual/flow,pyricau/flow,superboonie/flow,xfumihiro/flow,kidaa/flow,sdelaysam/flow,kaoree/flow,sdelaysam/flow,mlevytskiy/flow,square/flow,lynnmatrix/flow,venkatesh3007/flow,square/flow,Zhuinden/flowless