[doc]Fix following the release of 3.0.0

Author: Pierre-Sassoulas

ChangeLog

@@ -17,7 +17,7 @@ Release date: TBA
 
 What's New in astroid 3.0.0?
 =============================
-Release date: 2023-09-25
+Release date: 2023-09-26
 
 * Add support for Python 3.12, including PEP 695 type parameter syntax.
 

doc/release.md

@@ -41,6 +41,8 @@ Check the commit and then push to a release branch
   appropriate changelog in the description. This triggers the PyPI release.
 - Delete the `maintenance/X.Y-1.x` branch. (For example: `maintenance/2.3.x`)
 - Create a `maintenance/X.Y.x` (For example: `maintenance/2.4.x` from the `v2.4.0` tag.)
+  based on the tag from the release. The maintenance branch are protected you won't be
+  able to fix it after the fact if you create it from main.
 
 ## Backporting a fix from `main` to the maintenance branch