Update __init__.py

Author: MarkDaoust

google/generativeai/__init__.py

@@ -39,6 +39,8 @@
 See the [python quickstart](https://ai.google.dev/tutorials/python_quickstart) for more details.
 """
 from __future__ import annotations
+import warnings
+import textwrap
 
 from google.generativeai import version
 
@@ -77,6 +79,19 @@
 
 __version__ = version.__version__
 
+
+warnings.warn(
+    textwrap.dedent("""\
+    All support for the `google.generativeai` package has ended. It will no longer be receiving 
+    updates bug fixes. Please see the upgrade instructions in the [README][1]
+    
+    1: https://github.com/google-gemini/deprecated-generative-ai-python/blob/main/README.md
+    """,
+    FutureWarning,
+    stacklevel=2
+)
+
+
 del embedding
 del files
 del generative_models