Add missing dependabot ignore rules for unapproved GitHub Actions

Author: mraible

.github/dependabot.yml

@@ -29,3 +29,5 @@ updates:
         versions: [">=6.1.0"]
       - dependency-name: "peter-evans/create-pull-request"
         versions: [">=8.0.0"]
+      - dependency-name: "actions/upload-artifact"
+        versions: [">=6.0.0"]