Update llama-index-llms-openai requirement

Updates the requirements on llama-index-llms-openai to permit the latest version.

---
updated-dependencies:
- dependency-name: llama-index-llms-openai
  dependency-version: 0.5.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

topic/machine-learning/llama-index/requirements.txt

@@ -4,7 +4,7 @@ llama-index-embeddings-langchain<0.4
 llama-index-embeddings-openai<0.6
 llama-index-llms-azure-openai<0.5
 llama-index-llms-ollama<0.8
-llama-index-llms-openai<0.5
+llama-index-llms-openai<0.6
 llama-index-tools-mcp<0.3
 python-dotenv
 sqlalchemy-cratedb