Update breaking_changes.md

docs/general_info/breaking_changes.md

@@ -52,6 +52,12 @@ ANTHROPIC_MODELS=claude-1,claude-instant-1,claude-2
 
   - Choose from ANTHROPIC_MODELS which models you want to enable 🤖
 
+## v0.5.3
+
+Changed **AZURE_OPENAI_API_KEY** to **AZURE_API_KEY**:
+
+I had to change the environment variable from AZURE_OPENAI_API_KEY to AZURE_API_KEY, because the former would be read by langchain and cause issues when a user has both Azure and OpenAI keys set. This is a known issue in the langchain library https://github.com/hwchase17/langchainjs/issues/1687
+
 ## v0.5.0
 
 **Note: These changes only apply to users who are updating from a previous version of the app.**