dependabot.yml in slack-ruby-block-kit-0.18.0

- old
+ new

@@ -1,9 +1,10 @@
 version: 2
 updates:
 - package-ecosystem: bundler
   directory: "/"
   schedule:
-    interval: daily
+    interval: weekly
+    day: thursday
   open-pull-requests-limit: 99
   reviewers:
   - CGA1123