fix(dependabot): support nested dockerfiles

Author: ReenigneArcher

.github/dependabot.yml

@@ -15,7 +15,9 @@ updates:
     open-pull-requests-limit: 10
 
   - package-ecosystem: "docker"
-    directory: "/"
+    directories:
+      - "/"
+      - "/**"
     rebase-strategy: disabled
     schedule:
       interval: "cron"