docs: document Security Policy (#122)

README.md

@@ -77,6 +77,10 @@ estraverse.traverse(ast, {
 
 Issues and pull requests will be triaged and responded to as quickly as possible. We operate under the [ESLint Contributor Guidelines](http://eslint.org/docs/developer-guide/contributing), so please be sure to read them before contributing. If you're not sure where to dig in, check out the [issues](https://github.com/eslint/eslint-scope/issues).
 
+## Security Policy
+
+We work hard to ensure that ESLint Scope is safe for everyone and that security issues are addressed quickly and responsibly. Read the full [security policy](https://github.com/eslint/.github/blob/master/SECURITY.md).
+
 ## Build Commands
 
 * `npm test` - run all linting and tests