chore: add dependabot cooldown configs

.github/dependabot.yml

@@ -1,6 +1,8 @@
 version: 2
 updates:
 - package-ecosystem: docker
+  cooldown:
+    default-days: 4
   directories:
     - "/"
     - "/docker"
@@ -13,6 +15,10 @@ updates:
 
 - package-ecosystem: pip
   directory: "/"
+  cooldown:
+    default-days: 4
+    exclude:
+      - ccxt
   schedule:
     interval: weekly
     time: "03:00"
@@ -36,6 +42,8 @@ updates:
 
 - package-ecosystem: "github-actions"
   directory: "/"
+  cooldown:
+    default-days: 4
   schedule:
     interval: "weekly"
   open-pull-requests-limit: 10