add link to ScanNet++ v2 pairs

Author: yocabon

README.md

@@ -277,7 +277,8 @@ You have to download the datasets yourself from their official sources, agree to
 Links:  
 
 [ARKitScenes pairs](https://download.europe.naverlabs.com/ComputerVision/DUSt3R/arkitscenes_pairs.zip)  
-[ScanNet++ pairs](https://download.europe.naverlabs.com/ComputerVision/DUSt3R/scannetpp_pairs.zip)  
+[ScanNet++ v1 pairs](https://download.europe.naverlabs.com/ComputerVision/DUSt3R/scannetpp_pairs.zip)  
+[ScanNet++ v2 pairs](https://download.europe.naverlabs.com/ComputerVision/DUSt3R/scannetpp_v2_pairs.zip)  
 [BlendedMVS pairs](https://download.europe.naverlabs.com/ComputerVision/DUSt3R/blendedmvs_pairs.npy)  
 [WayMo Open dataset pairs](https://download.europe.naverlabs.com/ComputerVision/DUSt3R/waymo_pairs.npz)  
 [Habitat metadata](https://download.europe.naverlabs.com/ComputerVision/DUSt3R/habitat_5views_v1_512x512_metadata.tar.gz)