bar: warn on invalid height type in configuration

src/bar.cpp

@@ -172,6 +172,10 @@ waybar::Bar::Bar(struct waybar_output* w_output, const Json::Value& w_config)
     right_.set_spacing(spacing);
   }
 
+  if (config.isMember("height") && !config["height"].isUInt()) {
+  spdlog::warn("Invalid type for 'height', expected unsigned integer");
+  }
+
   height_ = config["height"].isUInt() ? config["height"].asUInt() : 0;
   width_ = config["width"].isUInt() ? config["width"].asUInt() : 0;