Update peerDependencies for angular 5
Update peerDependencies for angular 5

jfcere/ng2-markdown-to-html,jfcere/ng2-markdown-to-html,jfcere/ng2-markdown-to-html,jfcere/ng2-markdown-to-html,jfcere/ng2-markdown-to-html,jfcere/ng2-markdown-to-html