Dependabot is ignoring the weekly schedule

This change adds a specific day and time for the checks to take place
this will hopefully stop dependabot generating a pull request the minute
a package is updated on nuget

.github/dependabot.yml

@@ -4,6 +4,8 @@ updates:
     directory: "/"
     schedule:
       interval: "weekly"
+      day: "sunday"
+      time: "04:00"
     commit-message:
       prefix: "deps"
     open-pull-requests-limit: 1