ci: update dependabot configuration

This commit adds additional configuration for dependabot so that the PRs
are less of an annoyance to deal with. All version and security updates
will now be grouped into one PR at the end of the month, and will
properly target develop instead of main.

Signed-off-by: Ivin Joel Abraham <[email protected]>

Author: ivinjabraham

.github/dependabot.yml

@@ -3,4 +3,11 @@ updates:
   - package-ecosystem: "cargo"
     directory: "/"
     schedule:
-      interval: "weekly"
+      interval: "monthly"
+    open-pull-requests-limit: 1
+    target-branch: "develop"
+    groups:
+      all-dependencies:
+        applies-to: [version-updates, security-updates]
+        patterns:
+          - "*"