Bevy security policy (#20942)

# Objective

- Check the last unchecked point of
https://github.com/bevyengine/bevy/community

## Solution

- Add a security policy

---------

Co-authored-by: BD103 <59022059+BD103@users.noreply.github.com>

.github/ISSUE_TEMPLATE/config.yml

@@ -3,3 +3,6 @@ contact_links:
     url: https://github.com/bevyengine/bevy/discussions/categories/q-a
     about: Questions about how to use or contribute to Bevy belong in Github Discussions.
       You can use the search to check if someone already answered your question!
+  - name: Security Issue
+    url: https://github.com/bevyengine/bevy/security/advisories/new
+    about: If you believe you have found a security vulnerability, please DO NOT disclose it publicly until we’ve had a chance to fix it.

SECURITY.md

@@ -0,0 +1,16 @@
+# Security Policy
+
+## Supported Versions
+
+Only the latest released minor version of Bevy is supported.
+
+| Version                                                                                 | Supported          |
+| --------------------------------------------------------------------------------------- | ------------------ |
+| [![Crates.io](https://img.shields.io/crates/v/bevy.svg)](https://crates.io/crates/bevy) | :white_check_mark: |
+| Previous Versions                                                                       | :x:                |
+
+## Reporting a Vulnerability
+
+If you believe you have found a security vulnerability, please DO NOT disclose it publicly until we’ve had a chance to fix it.
+
+Please don’t report security vulnerabilities via GitHub issues, instead [report them privately](https://docs.github.com/en/code-security/security-advisories/guidance-on-reporting-and-writing-information-about-vulnerabilities/privately-reporting-a-security-vulnerability) via the [Security Advisories](https://github.com/bevyengine/bevy/security/advisories/new) page.