Update dependabot.yml

.github/dependabot.yml

@@ -14,6 +14,9 @@ updates:
     directory: "/"
     schedule:
       interval: "daily"
+    ignore:
+      - dependency-name: "php-actions/phpunit"
+        versions: ["5", "6", "7", "8", "9"]
 
   - package-ecosystem: "npm"
     directory: "/"