Remove --php-version flag from DDEV instructions

This is now the project type default, so it's not needed!

Author: AugustMiller

docs/5.x/install.md

@@ -32,7 +32,7 @@ While we [strongly recommend](#why-ddev) DDEV for new Craft projects, [alternate
 1. Create DDEV configuration files:
 
     ```bash
-    ddev config --project-type=craftcms --docroot=web --php-version=8.2
+    ddev config --project-type=craftcms --docroot=web
     ```
 
 1. Scaffold the project from the official [starter project](https://github.com/craftcms/craft):