chore(dependabot): adds examples directories separately (#2505)

Summary:
**Summary**

Adds examples directories containing a `package.json` file individually. Resolves #2420.

**Test Plan**

Laser eyes {emoji:1f440}

Pull Request resolved: #2505

Reviewed By: mrkev

Differential Revision: D22617258

Pulled By: claudiopro

fbshipit-source-id: b56fb58c3e3d87e814b00faec850a5968d2455b8

.dependabot/config.yml

@@ -1,7 +1,13 @@
 version: 1
 update_configs:
   - package_manager: "javascript"
-    directory: "/examples/draft-0-10-0/"
+    directory: "/examples/draft-0-10-0/playground"
+    update_schedule: "monthly"
+  - package_manager: "javascript"
+    directory: "/examples/draft-0-10-0/tex"
+    update_schedule: "monthly"
+  - package_manager: "javascript"
+    directory: "/examples/draft-0-10-0/universal"
     update_schedule: "monthly"
   - package_manager: "javascript"
     directory: "/"