Add default author email to setup script

- Adds default@example.com as default value for AUTHOR_EMAIL variable in ./setup.py.
- Fixes a Pylance argument error that questions the possibility of os.getenv() function returning an empty value, contrary to the accepted data types of setup(author_email), which is just strings.
- Fixes #10.

Author: LuisAPI

setup.py

@@ -10,7 +10,7 @@ def read_requirements():
 
 # Load environment variables
 load_dotenv()
-AUTHOR_EMAIL = os.getenv('AUTHOR_EMAIL')
+AUTHOR_EMAIL = os.getenv('AUTHOR_EMAIL', "default@example.com")
 
 setup(
     name='YouTubeWikiBot',