fix typo error in readme
fix typo error in readme

piosz/heapster,johanneswuerbach/heapster,Stackdriver/heapster,aegixx/heapster,AlmogBaku/heapster,bruceauyeung/heapster,titilambert/heapster,shilpamayanna/heapster,huangyuqi/heapster,piosz/heapster,bluebreezecf/heapster,burmanm/heapster,luxas/heapster,whuwxl/heapster,andyxning/heapster,Stackdriver/heapster,jackzampolin/heapster,AlmogBaku/heapster,burmanm/heapster,aegixx/heapster,bruceauyeung/heapster,andyxning/heapster,adfin/statster,shilpamayanna/heapster,huangyuqi/heapster,bluebreezecf/heapster,liubog2008/heapster,jackzampolin/heapster,krzyzacy/heapster,titilambert/heapster,johanneswuerbach/heapster,saiwl/heapster,mwringe/heapster,saiwl/heapster,whuwxl/heapster,taimir/heapster,krzyzacy/heapster,adfin/statster,taimir/heapster,luxas/heapster,mwringe/heapster,liubog2008/heapster