Fixing minor typo in readme.
Fixing minor typo in readme.

JaKXz/grunt,imjerrybao/grunt,vladikoff/grunt,shama/grunt,FeodorFitsner/grunt,youmyyou/grunt,eelve/grunt,modulexcite/grunt,yosiazwan/grunt,abraheem/grunt,thecc4re/gruntjs,rwaldron/grunt,paulcbetts/grunt,pandeysoni/grunt,r14r-work/fork_grunt_master,paladox/grunt,felixgrey/grunt,q310550690/grunt,vojtajina/grunt,yuhualingfeng/grunt,thejameskyle/grunt,ThiagoGarciaAlves/grunt,IveWong/grunt,yonglehou/grunt,lkiarest/grunt,goodeggs/grunt,r14r/fork_grunt_master,Chhunlong/grunt,coldrye-collaboration/grunt,zackexplosion/grunt,fscherwi/grunt,arosa81/grunt