GH Actions: minor tweak after release of PHPCS 3.8.0

Author: jrfnl

.github/workflows/test.yml

@@ -40,7 +40,7 @@ jobs:
           - php: '8.3'
             phpcs_version: 'dev-master'
           - php: '8.3'
-            phpcs_version: '3.6.1'
+            phpcs_version: '3.8.0'
 
           - php: '8.2'
             phpcs_version: 'dev-master'