minor #16190 [Setup] PHP 8.1 is the last release (alexislefebvre)

This PR was merged into the 6.0 branch.

Discussion
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[Setup] PHP 8.1 is the last release

The text was saying:

> Before creating your first Symfony application you must:
>
> - Install **PHP 8.0.2** or higher […]
>   - Note that all newer, released versions of PHP will be supported during the lifetime of each Symfony release (including new major versions). For example, **PHP 8.0** is supported.

(emphasis mine)

I found it strange.

Commits
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167f561 PHP 8.1 is the last release

Author: javiereguiluz

setup.rst

@@ -23,7 +23,7 @@ Before creating your first Symfony application you must:
 
   * Note that all newer, released versions of PHP will be supported during the
     lifetime of each Symfony release (including new major versions).
-    For example, PHP 8.0 is supported.
+    For example, PHP 8.1 is supported.
 * `Install Composer`_, which is used to install PHP packages.
 
 Optionally, you can also `install Symfony CLI`_. This creates a binary called