add a security policy (#2238)

* add a security policy

* fix typo

* Update SECURITY.md

---------

Co-authored-by: Prithvi Shahi <50885601+p-shahi@users.noreply.github.com>

SECURITY.md

@@ -0,0 +1,20 @@
+# Security Policy
+
+go-libp2p is still in development. This means that there may be problems in our protocols,
+or there may be mistakes in our implementations.
+We take security vulnerabilities very seriously. If you discover a security issue,
+please bring it to our attention right away!
+
+## Reporting a Vulnerability
+
+If you find a vulnerability that may affect live deployments -- for example, by exposing
+a remote execution exploit -- please [**report privately**](https://github.com/libp2p/go-libp2p/security/advisories/new).
+Please **DO NOT file a public issue**.
+
+If the issue is an implementation weakness that cannot be immediately exploited or
+something not yet deployed, just discuss it openly.
+If you need assistance, please reach out to [security@libp2p.io](mailto:security@libp2p.io).
+
+## Reporting a non security bug
+
+For non-security bugs, please simply file a GitHub [issue](https://github.com/libp2p/go-libp2p/issues/new).