Switchd dependabot to monthly checking

Author: dirkkul

.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"
     ignore:
       - dependency-name: "grpcio"
       - dependency-name: "grpcio-tools"