prepare announcement for version 1.3
prepare announcement for version 1.3

Akkrite/snakeyaml,youxinren/snakeyaml,ldh0826/snakeyaml,Fighter777/snakeyaml,umeding/snakeyaml,yeison/snakeyaml,UcasRichard/snakeyaml,SorinS/snakeyaml,joy32812/snakeyaml,yskumar007/snakeyaml,votinhthieugia/snakeyaml,cuizhennan/snakeyaml,yishenggudou/snakeyaml,AssafMashiah/assafmashiah-yaml,nxbdi/snakeyaml,mc-nekoneko/snakeyaml,RussellSpitzer/snakeyaml,Mause/snakeyaml,mapiman/snakeyaml,virustotalop/snakeyaml,jeremypepper/snakeyaml,thinkofdeath/snakeyaml,ilantoren/snakeyaml,marcuskara/snakeyaml