Update dependabot.yml

Author: vb2ae

.github/dependabot.yml

@@ -1,11 +1,8 @@
-# To get started with Dependabot version updates, you'll need to specify which
-# package ecosystems to update and where the package manifests are located.
-# Please see the documentation for all configuration options:
-# https://docs.github.com/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
-
 version: 2
 updates:
-  - package-ecosystem: "bundler" # See documentation for possible values
-    directory: "/" # Location of package manifests
-    schedule:
-      interval: "weekly"
+- package-ecosystem: bundler
+  directory: "/"
+  schedule:
+    interval: monthly
+    time: "03:00"
+    timezone: US/Eastern