Add release notes for bucketing v2
Add release notes for bucketing v2

Release notes for a3604c4bb91f899ef562c8e270de8f98536e5c0f.

smartnews/presto,electrum/presto,11xor6/presto,dain/presto,erichwang/presto,electrum/presto,hgschmie/presto,losipiuk/presto,martint/presto,dain/presto,Praveen2112/presto,dain/presto,treasure-data/presto,hgschmie/presto,11xor6/presto,electrum/presto,martint/presto,ebyhr/presto,erichwang/presto,Praveen2112/presto,hgschmie/presto,ebyhr/presto,hgschmie/presto,dain/presto,ebyhr/presto,erichwang/presto,11xor6/presto,erichwang/presto,electrum/presto,martint/presto,treasure-data/presto,treasure-data/presto,losipiuk/presto,dain/presto,treasure-data/presto,losipiuk/presto,treasure-data/presto,smartnews/presto,Praveen2112/presto,smartnews/presto,ebyhr/presto,hgschmie/presto,losipiuk/presto,erichwang/presto,electrum/presto,smartnews/presto,martint/presto,11xor6/presto,martint/presto,Praveen2112/presto,losipiuk/presto,ebyhr/presto,smartnews/presto,11xor6/presto,treasure-data/presto,Praveen2112/presto