Update help text

Signed-off-by: Chin Yeung Li <[email protected]>

Author: chinyeungli

src/attributecode/cmd.py

@@ -110,7 +110,7 @@ def cli():
     type=click.Path(exists=False, dir_okay=False, resolve_path=True))
 
 @click.option('--filter', nargs=1, multiple=True, 
-    help='Filter for the output inventory.')
+    help='Filter for the output inventory.' e.g. "license_expression=gpl-2.0')
 
 @click.option('-f', '--format', is_flag=False, default='csv', show_default=True,
     type=click.Choice(['json', 'csv']),