dependabot.yml: update to match main configuration

Author: BrewTestBot

.github/dependabot.yml

@@ -6,6 +6,7 @@ updates:
   directory: "/"
   schedule:
     interval: weekly
+    cron: 0 8 * * 1
   allow:
   - dependency-type: all
   ignore:
@@ -17,7 +18,8 @@ updates:
 - package-ecosystem: bundler
   directory: "/"
   schedule:
-    interval: daily
+    interval: weekly
+    cron: 0 8 * * 1
   allow:
   - dependency-type: all