doc: warning added for deprectaion of gpt-3.5 as default model for OpenAI generators (#8300)

* warning added for gpt3.5 usage

* Revert "warning added for gpt3.5 usage"

This reverts commit 035a0ab9eaa9306171439fe128a78b7898ffe486.

* update openaigenerator and openaichatgenerator with warnings

* if cond removed

* update description

* adding release notes

* linting

---------

Co-authored-by: David S. Batista <dsbatista@gmail.com>

haystack/components/generators/chat/openai.py

@@ -5,6 +5,7 @@
 import copy
 import json
 import os
+import warnings
 from typing import Any, Callable, Dict, List, Optional, Union
 
 from openai import OpenAI, Stream
@@ -117,6 +118,11 @@ class OpenAIChatGenerator:
             Maximum number of retries to contact OpenAI after an internal error.
             If not set, it defaults to either the `OPENAI_MAX_RETRIES` environment variable, or set to 5.
         """
+        warnings.warn(
+            "In the upcoming releases 'gpt-3.5-turbo' will be replaced by 'gpt-4o-mini' as the default model",
+            DeprecationWarning,
+        )
+
         self.api_key = api_key
         self.model = model
         self.generation_kwargs = generation_kwargs or {}

haystack/components/generators/openai.py

@@ -3,6 +3,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 import os
+import warnings
 from typing import Any, Callable, Dict, List, Optional, Union
 
 from openai import OpenAI, Stream
@@ -102,6 +103,11 @@ class OpenAIGenerator:
             from the `OPENAI_MAX_RETRIES` environment variable or set to 5.
 
         """
+        warnings.warn(
+            "In the upcoming releases 'gpt-3.5-turbo' will be replaced by 'gpt-4o-mini' as the default model",
+            DeprecationWarning,
+        )
+
         self.api_key = api_key
         self.model = model
         self.generation_kwargs = generation_kwargs or {}

releasenotes/notes/deprecated-gpt-3.5-as-default-model-d03cafe1fdc2ada2.yaml

@@ -0,0 +1,4 @@
+---
+deprecations:
+  - |
+    The 'gpt-3.5-turbo' as the default model for the `OpenAIGenerator` and `OpenAIChatGenerator` will be replaced by 'gpt-4o-mini'.