do not use dev dependencies for php 8

Author: goetas

.github/workflows/continuous-integration.yml

@@ -25,13 +25,12 @@ jobs:
           - "7.2"
           - "7.3"
           - "7.4"
+          - "8.0"
         deps:
           - "normal"
         include:
           - deps: "low"
             php-version: "7.2"
-          - deps: "dev"
-            php-version: "8.0"
 
     steps:
       - name: "Checkout"