Rename package-ecosystem from 'actions' to 'github-actions' (#144)

Author: rajbos

.github/dependabot.yml

@@ -9,7 +9,7 @@ updates:
         patterns:
           - "*"
 
-  - package-ecosystem: "actions"
+  - package-ecosystem: "github-actions"
     directory: "/"
     schedule:
       interval: "weekly"