update .scrutinizer.yml

Author: fenric

.scrutinizer.yml

@@ -1,4 +1,7 @@
 build:
+  environment:
+    php:
+      version: '8.0'
   nodes:
     analysis:
       tests:
@@ -7,7 +10,7 @@ build:
     coverage:
       tests:
         override:
-          - command: php vendor/bin/phpunit --coverage-clover coverage.xml
+          - command: XDEBUG_MODE=coverage php vendor/bin/phpunit --coverage-clover coverage.xml
             coverage:
               file: coverage.xml
               format: clover