CI: exclude PHP 8.5 opcache job (opcache is built-in)

Author: pronskiy

.github/workflows/tests.yml

@@ -15,6 +15,9 @@ jobs:
             matrix:
                 php: ['8.2', '8.3', '8.4', '8.5']
                 opcache: [false, true]
+                exclude:
+                    - php: '8.5'
+                      opcache: true
         steps:
             -   uses: actions/checkout@v6