Update SECURITY.md

Author: pradosh-arduino

SECURITY.md

@@ -11,9 +11,19 @@ here are the version that is currently supported
 | 2.5.x   | :white_check_mark: |
 | 2.4.x   | :white_check_mark: |
 | 2.3.x   | :white_check_mark: |
-| 2.2.x   | :white_check_mark:                |
+| 2.2.x   | :white_check_mark: |
 | < 2.1.0 | :x:                |
 
+## Release Structure
+
+|  Name   |
+|---------|
+| LTS     |
+| Release |
+| Nightly |
+| Beta    |
+| Alpha   |
+
 ## Reporting a Vulnerability
 
 Please Report any Vulnerability to [issues](https://github.com/pradosh-arduino/Melon-Language/issues) it will really help A LOT!