Start development with the latest PHP

We drop PHP8.1 for the next DOMjudge release.

Author: vmcj

SECURITY.md

@@ -4,7 +4,7 @@
 
 | DOMjudge Version | Supported          | PHP version supported |
 |------------------| ------------------ |-----------------------|
-| main branch      | :warning:          | 8.1-8.4               |
+| main branch      | :warning:          | 8.2-                  |
 | 9.0.x            | :white_check_mark: | 8.1-8.4               |
 | 8.3.x            | :white_check_mark: | 8.1-8.3               |
 | < 8.3            | :x:                | :x:                   |