Fix: Use FileNotFoundError for file not found in main.py

Replaced IOError with FileNotFoundError on line 320 of main.py to use a more specific and appropriate exception for file not found errors.

Author: creepereye1204

src/dotenv/main.py

@@ -319,8 +319,6 @@ def _is_debugger():
     if raise_error_if_not_found:
         raise FileNotFoundError("File not found")
     return ""
-        
-
 
 
 def load_dotenv(