docs: added release notes for 0.3.12.
docs: added release notes for 0.3.12.

ArxdSilva/tsuru,mderaldo/tsuru,ggarnier/tsuru,mderaldo/tsuru,tuxmonteiro/tsuru,hcxiong/tsuru,gwmoura/tsuru,RichardKnop/tsuru,tsuru/tsuru,tuxmonteiro/tsuru,Endika/tsuru,tsuru/tsuru,Endika/tsuru,gciotta/tsuru,jblancett/tsuru,mderaldo/tsuru,firebitsbr/tsuru,hugoantunes/tsuru,tuxmonteiro/tsuru,ArxdSilva/tsuru,ggarnier/tsuru,gwmoura/tsuru,gwmoura/tsuru,kgrvamsi/tsuru,kgrvamsi/tsuru,4eek/tsuru,cgvarela/tsuru,guilhermebr/tsuru,guilhermebr/tsuru,Endika/tsuru,firebitsbr/tsuru,tsuru/tsuru,tsuru/tsuru,cgvarela/tsuru,hcxiong/tsuru,firebitsbr/tsuru,ArxdSilva/tsuru,hugoantunes/tsuru,RichardKnop/tsuru,gciotta/tsuru,gciotta/tsuru,RichardKnop/tsuru,guilhermebr/tsuru,ggarnier/tsuru,ggarnier/tsuru,cezarsa/tsuru,ArxdSilva/tsuru,cgvarela/tsuru,cezarsa/tsuru,guilhermebr/tsuru,cezarsa/tsuru,kgrvamsi/tsuru,jblancett/tsuru,4eek/tsuru,jblancett/tsuru,4eek/tsuru,cezarsa/tsuru,hcxiong/tsuru