fix: Add --license placeholder for future use (#101)

plugin-pb-go [1.15.0](cloudquery/plugin-pb-go#196) now uses `--license` when invoking plugins, if one is set by the cli.

Author: disq

cloudquery/sdk/serve/plugin.py

@@ -148,6 +148,13 @@ def _register_serve_command(self, subparsers):
             default="",
             help="Open Telemetry HTTP collector endpoint (for development only) (placeholder for future use)",
         )
+        # ignored for now
+        serve_parser.add_argument(
+            "--license",
+            type=str,
+            default="",
+            help="set offline license file (placeholder for future use)",
+        )
         serve_parser.add_argument(
             "--address",
             type=str,