data: add validation subset

.gitattributes

@@ -14,3 +14,4 @@ zhanglabdata_chest_xray/train.zip filter=lfs diff=lfs merge=lfs -text
 american_sign_language/test.zip filter=lfs diff=lfs merge=lfs -text
 american_sign_language/valid.zip filter=lfs diff=lfs merge=lfs -text
 vertebral_keypoints/v1/vertebral-keypoints-train-64.zip filter=lfs diff=lfs merge=lfs -text
+vertebral_keypoints/v1/vertebral-keypoints-valid-16.zip filter=lfs diff=lfs merge=lfs -text

vertebral_keypoints/v1/vertebral-keypoints-valid-16.zip

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c04c363cffdb6cacd605f83d07fce5f257c3fab2b15d232bd5d7ba43a6f9507a
+size 431219