Migrate CompleteSecurityBody to TypeScript

src/components/views/auth/CompleteSecurityBody.tsx

@@ -19,7 +19,7 @@ import { replaceableComponent } from "../../../utils/replaceableComponent";
 
 @replaceableComponent("views.auth.CompleteSecurityBody")
 export default class CompleteSecurityBody extends React.PureComponent {
-    render() {
+    public render(): React.ReactNode {
         return <div className="mx_CompleteSecurityBody">
             { this.props.children }
         </div>;