docs: added a basic security policy (#541)

## PR Checklist

- [x] Addresses an existing open issue: fixes #540 
- [x] That issue was marked as [`status: accepting
prs`](https://github.com/JoshuaKGoldberg/template-typescript-node-package/issues?q=is%3Aopen+is%3Aissue+label%3A%22status%3A+accepting+prs%22)
- [x] Steps in
[CONTRIBUTING.md](https://github.com/JoshuaKGoldberg/template-typescript-node-package/blob/main/.github/CONTRIBUTING.md)
were taken

## Overview

Adds a very basic security policy based on
https://github.com/typescript-eslint/typescript-eslint/blob/a91bb9e264544fc635a44468c2543b94fa83ac1c/.github/SECURITY.md.

Author: JoshuaKGoldberg

.github/SECURITY.md

@@ -0,0 +1,9 @@
+# Security Policy
+
+We take all security vulnerabilities seriously.
+If you have a vulnerability or other security issues to disclose:
+
+- Thank you very much, please do!
+- Please send them to us by emailing `[email protected]`
+
+We appreciate your efforts and responsible disclosure and will make every effort to acknowledge your contributions.

src/hydrate/steps/writing/creation/dotGitHub/rootFiles.ts

@@ -335,6 +335,16 @@ Otherwise we may not be able to review your PR. -->
 ## Overview
 
 <!-- Description of what is changed and how the code change does that. -->
+`,
+		"SECURITY.md": `# Security Policy
+
+We take all security vulnerabilities seriously.
+If you have a vulnerability or other security issues to disclose:
+
+- Thank you very much, please do!
+- Please send them to us by emailing \`${email}\`
+
+We appreciate your efforts and responsible disclosure and will make every effort to acknowledge your contributions.
 `,
 		"renovate.json": JSON.stringify(
 			{