ci: stop dependabot from scanning the repository root for pip (#284)

Author: mwbrooks

.github/dependabot.yml

@@ -2,7 +2,6 @@ version: 2
 updates:
   - package-ecosystem: "pip"
     directories:
-      - "/"
       - "/openai-agents-sdk"
       - "/pydantic-ai"
       - "/claude-agent-sdk"