Update supported versions table for 5.4 release (#8331)

5.4.0 was released on July 19th 2026. Per the minor version support policy,
security support for 5.1 ended with that release (3 new minors published),
and active support moved to 5.4.

Matches the version map and supported versions tables in the wiki.

Author: dereuromark

docs/en/intro/supported-versions.md

@@ -4,11 +4,11 @@ See [CakePHP Development Process](../appendices/cakephp-development-process.md)
 
 ## CakePHP Supported Versions
 
-This table was last updated in February 2026.
+This table was last updated in August 2026.
 
 | Major Version | Supported Version | PHP-Version    | Active Support | Security Support     |
 |---------------|-------------------|----------------|----------------|----------------------|
-| `5.x`         | `5.1` to `5.3`    | `8.1` to `8.5` | `5.3+`         | ✅                    |
+| `5.x`         | `5.2` to `5.4`    | `8.1` to `8.5` | `5.4+`         | ✅                    |
 | `4.x`         | `4.4` to `4.6`    | `7.2` to `8.3` | ❌              | September 10th, 2026 |
 | `3.x`         | None              | `5.6` to `7.4` | ❌              | ❌                    |
 | `2.x`         | None              | `5.4` to `7.4` | ❌              | ❌                    |