update license attribute
update license attribute

specifying the type and URL is deprecated:

https://docs.npmjs.com/files/package.json#license
http://npm1k.org/
q310550690/grunt,modulexcite/grunt,shama/grunt,paladox/grunt,imjerrybao/grunt,lkiarest/grunt,r14r-work/fork_grunt_master,r14r/fork_grunt_master,Chhunlong/grunt,thecc4re/gruntjs,youmyyou/grunt,abraheem/grunt,felixgrey/grunt,thejameskyle/grunt,IveWong/grunt,fscherwi/grunt,yosiazwan/grunt,ThiagoGarciaAlves/grunt,yuhualingfeng/grunt,eelve/grunt,zackexplosion/grunt,yonglehou/grunt,arosa81/grunt