Revise PHP version support and security reporting guidelines

Updated PHP version support table and improved wording for reporting security issues.

Signed-off-by: Alex Karajos <alex.merlin.1985@gmail.com>

Author: alexmerlin

SECURITY.md

@@ -5,7 +5,8 @@
 | Version | Supported          | PHP Version                                                                                                    |
 |---------|--------------------|----------------------------------------------------------------------------------------------------------------|
 | 4.x     | :white_check_mark: | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-navigation/4.2.0) |
-| <= 3.x  | :x:                |                                                                                                                |
+| 3.x     | :white_check_mark: | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-navigation/3.6.0) |
+| <= 2.x  | :x:                |                                                                                                                |
 
 ## Reporting Potential Security Issues
 
@@ -19,7 +20,7 @@ When reporting issues, please provide the following information:
 - A summary of the security vulnerability and impact
 
 We request that you contact us via the email address above and give the project contributors a chance to resolve the vulnerability and issue a new release prior to any public exposure;
-this helps protect the project's users, and provides them with a chance to upgrade and/or update in order to protect their applications.
+this helps protect the project's users and provides them with a chance to upgrade and/or update to protect their applications.
 
 ## Policy