Add warning when load_dotenv has been disabled

Author: matthewfranglen

src/dotenv/main.py

@@ -354,6 +354,9 @@ def load_dotenv(
         return False
 
     if dotenv_path is None and stream is None:
+        logger.warning(
+            "python-dotenv has been disabled by DOTENV_AUTOLOAD_DISABLED environmental variable"
+        )
         dotenv_path = find_dotenv()
 
     dotenv = DotEnv(