chore: change dependabot update interval from weekly to monthly

Author: jondricek

.github/dependabot.yml

@@ -8,7 +8,7 @@ updates:
   - package-ecosystem: "pip" # See documentation for possible values
     directory: "/" # Location of package manifests
     schedule:
-      interval: "weekly"
+      interval: "monthly"
       day: "saturday"
       time: "09:00"
       timezone: "America/New_York"