Update php.yml

Author: cornelius-behrend

.github/workflows/php.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         operating-system: ['ubuntu-latest']
-        php-versions: ['7.3', '7.4', '8.0']
+        php-versions: ['7.3', '7.4']
         phpunit-versions: ['latest']
         include:
         - operating-system: 'ubuntu-latest'