Add Tidelift links (#1004)

* Add support and security links to TideLift

Readme.md

@@ -562,3 +562,9 @@ More Demos can be found in the [examples](https://github.com/tj/commander.js/tre
 ## License
 
 [MIT](https://github.com/tj/commander.js/blob/master/LICENSE)
+
+## Support
+
+[Professionally supported commander is now available](https://tidelift.com/subscription/pkg/npm-commander?utm_source=npm-commander&utm_medium=referral&utm_campaign=readme)
+
+Tidelift gives software development teams a single source for purchasing and maintaining their software, with professional grade assurances from the experts who know it best, while seamlessly integrating with existing tools.

SECURITY.md

@@ -0,0 +1,15 @@
+# Security Policy
+
+## Supported Versions
+
+| Version | Supported          |
+| ------- | ------------------ |
+| 3.x     | :white_check_mark: |
+| 2.x     | :white_check_mark: |
+| < 2     | :x:                |
+
+## Reporting a Vulnerability
+
+To report a security vulnerability, please use the
+[Tidelift security contact](https://tidelift.com/security).
+Tidelift will coordinate the fix and disclosure.