Add lint warning for empty url (#25182)

lib/python/qmk/cli/lint.py

@@ -171,6 +171,14 @@ def _handle_invalid_features(kb, info):
     return ok
 
 
+def _handle_invalid_config(kb, info):
+    """Check for invalid keyboard level config
+    """
+    if info.get('url') == "":
+        cli.log.warning(f'{kb}: Invalid keyboard level config detected - Optional field "url" should not be empty.')
+    return True
+
+
 def _chibios_conf_includenext_check(target):
     """Check the ChibiOS conf.h for the correct inclusion of the next conf.h
     """
@@ -255,6 +263,9 @@ def keyboard_check(kb):  # noqa C901
     if not _handle_invalid_features(kb, kb_info):
         ok = False
 
+    if not _handle_invalid_config(kb, kb_info):
+        ok = False
+
     invalid_files = git_get_ignored_files(f'keyboards/{kb}/')
     for file in invalid_files:
         if 'keymap' in file: