[Releases] Update stable and old-stable branch (#1254)

* [Releases] Update stable and old-stable branch

* Update releases.md

Co-authored-by: Kévin Dunglas <[email protected]>

Author: Jibbarth

extra/releases.md

@@ -4,9 +4,9 @@ API Platform follows the [Semantic Versioning](https://semver.org) strategy.
 
 Only 3 versions are maintained at the same time:
 
-* **stable** (currently the **2.5** branch): regular bug fixes are integrated in this version
-* **old-stable** (currently **2.4** branch): security fixes are integrated in this version, regular bug fixes are **not** backported in it
-* **development** (**master** branch): new features target this branch
+* **stable** (currently the **2.6** branch): regular bug fixes are integrated in this version
+* **old-stable** (currently **2.5** branch): security fixes are integrated in this version, regular bug fixes are **not** backported in it
+* **development** (**main** branch): new features target this branch
 
 Older versions (1.x, 2.0...) **are not maintained**. If you still use them, you must upgrade as soon as possible.