Update dependabot.yml

Author: giarc3

.github/dependabot.yml

@@ -1,9 +1,15 @@
 version: 2
 updates:
-  - package-ecosystem: "cargo"
-    directory: "/"
-    schedule:
-      interval: "monthly"
+- package-ecosystem: "cargo"
+  directory: "/"
+  schedule:
+    interval: "monthly"
+  groups:
+    dependencies:
+      patterns:
+      - "*"
+      exclude-patterns:
+      - "rand*"
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule: