feat: Adds --update-cache flag to 'server'.

map_machine/slippy/server.py

@@ -74,6 +74,7 @@ def run_server(options: argparse.Namespace) -> None:
     try:
         handler = TileServerHandler
         handler.cache = Path(options.cache)
+        handler.update_cache = options.update_cache
         handler.options = options
         server = HTTPServer(("", options.port), handler)
         logging.info(f"Server started on port {options.port}.")

map_machine/ui/cli.py

@@ -270,6 +270,12 @@ def add_server_arguments(parser: argparse.ArgumentParser) -> None:
         default="cache",
         metavar="<path>",
     )
+    parser.add_argument(
+        "--update-cache",
+        action=argparse.BooleanOptionalAction,
+        default=True,
+        help="allow writing to cache",
+    )
     parser.add_argument(
         "--port",
         help="port number",