Fix a typo in health plugin readme (#2274)
Fix a typo in health plugin readme (#2274)


johnbelamaric/coredns,ii/coredns,miekg/coredns,chrisohaver/coredns,coredns/coredns,miekg/coredns,johnbelamaric/coredns,yongtang/coredns,ii/coredns,jremond/coredns,jremond/coredns