[github-331] update dependabot settings. This close #331

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1901163 13f79535-47bb-0310-9956-ffa450edef68

.github/dependabot.yml

@@ -9,3 +9,7 @@ updates:
     directory: "/" # Location of package manifests
     schedule:
       interval: "daily"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"