Do coverage on PHP 8.2

Author: tbradsha

.github/files/generate-ci-matrix.php

@@ -121,6 +121,7 @@
 $matrix[] = array(
 	'name'    => 'Code coverage',
 	'script'  => 'test-coverage',
+	'php'     => '8.2', // @todo: bump this to PHP 8.4 after working out all its quirks
 	'wp'      => 'latest',
 	'timeout' => 40, // 2024-11-12: Successful runs seem to take ~14 minutes.
 );