fix arxiv url

Author: RussTedrake

README.md

@@ -1,6 +1,6 @@
 # Motion Planning around Obstacles with Convex Optimization
 
-This repository contains the code to reproduce the examples in the paper [Motion Planning around Obstacles with Convex Optimization](https://arxiv.org/abs/2106.09610) by Tobia Marcucci, Mark Petersen, David von Wrangel, and Russ Tedrake.
+This repository contains the code to reproduce the examples in the paper [Motion Planning around Obstacles with Convex Optimization](https://arxiv.org/abs/2205.04422) by Tobia Marcucci, Mark Petersen, David von Wrangel, and Russ Tedrake.
 
 To use [Graphs of Convex Sets (GCS) Trajectory Optimization](https://drake.mit.edu/doxygen_cxx/classdrake_1_1planning_1_1trajectory__optimization_1_1_gcs_trajectory_optimization.html) in your own code, we recommend that you use the version in [Drake](http://drake.mit.edu), which is being actively developed and improved.