changed gradle maven publish script to use environment variables for username and passsword
changed gradle maven publish script to use environment variables for username and passsword

jaohoang/StickyListHeaders,DenisMondon/StickyListHeaders,chwnFlyPig/StickyListHeaders,emilsjolander/StickyListHeaders,hejunbinlan/StickyListHeaders,msdgwzhy6/StickyListHeaders,peterdocter/StickyListHeaders,emnrd-ito/StickyListHeaders,huy510cnt/Sticky_ListHeaders,wlrhnh-David/StickyListHeaders,mrljdx/StickyListHeaders,yunfengsa/StickyListHeaders,b-cuts/StickyListHeaders,paul0952710801/StickyListHeaders,tomoyuki28jp/StickyListHeaders,jianxiansining/StickyListHeaders,littlezan/StickyListHeaders,jmiguel2902/StickyListHeaders,VictorS-Zhao/StickyListHeaders,dongzhouT/StickyListHeaders,xiazhenshui/StickyListHeaders,lxhxhlw/StickyListHeaders,huyunkai/StickyListHeaders,NewComerBH/StickyListHeaders,hgl888/StickyListHeaders,sam-yr/StickyListHeaders,AndrewGeorge/StickyListHeaders,Akylas/StickyListHeaders,selmanon/StickyListHeaders,CyanogenMod/android_external_emilsjolander_stickylistheaders,wswenyue/StickyListHeaders,silent-nischal/StickyListHeaders,pacificIT/StickyListHeaders,LivioGama/StickyListHeaders,nilesh14/FMC,neonaldo/StickyListHeaders,mtotschnig/StickyListHeaders,wisavalite/StickyListHeaders,denispyr/StickyListHeaders,maxi182/StickyListHeaders