👷 run dependabot monthly (previously weekly)

No need to waste resources by running too frequently, as no release is triggered every week

Author: davidB

.github/dependabot.yml

@@ -3,12 +3,12 @@ updates:
   - package-ecosystem: "cargo"
     directory: "/"
     schedule:
-      interval: "weekly"
+      interval: "monthly"
     allow:
       - dependency-type: "direct"
   - package-ecosystem: "github-actions"
     # Workflow files stored in the
     # default location of `.github/workflows`
     directory: "/"
     schedule:
-      interval: "weekly"
+      interval: "monthly"