[ci skip] Bump phpunit version in docs

Author: MGatner

admin/module/tests/README.md

@@ -12,7 +12,7 @@ use to test your module. Those details can be found in the documentation.
 ## Requirements
 
 It is recommended to use the latest version of PHPUnit. At the time of this 
-writing we are running version 7.5.1. Support for this has been built into the 
+writing we are running version 8.5.2. Support for this has been built into the 
 **composer.json** file that ships with CodeIgniter and can easily be installed 
 via [Composer](https://getcomposer.org/) if you don't already have it installed globally.
 

admin/starter/tests/README.md

@@ -12,7 +12,7 @@ use to test your application. Those details can be found in the documentation.
 ## Requirements
 
 It is recommended to use the latest version of PHPUnit. At the time of this 
-writing we are running version 7.5.1. Support for this has been built into the 
+writing we are running version 8.5.2. Support for this has been built into the 
 **composer.json** file that ships with CodeIgniter and can easily be installed 
 via [Composer](https://getcomposer.org/) if you don't already have it installed globally.
 

tests/README.md

@@ -8,7 +8,7 @@ use to test your application. Those details can be found in the documentation.
 ## Requirements
 
 It is recommended to use the latest version of PHPUnit. At the time of this 
-writing we are running version 7.5.1. Support for this has been built into the 
+writing we are running version 8.5.2. Support for this has been built into the 
 **composer.json** file that ships with CodeIgniter and can easily be installed 
 via [Composer](https://getcomposer.org/) if you don't already have it installed globally.