replaced transformer-xl-base with segatron-xl-base

I uploaded a transformer-xl-base into this segatron-xl-base model card. Fixed in this commit.

model.pt

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:0484ea78b352a12cd4e3dd6bb7fa1ad9aaa8254372f3e433df4faca7b96c56ce
-size 302334639
+oid sha256:eec8c711ed5c5accc3e325f78f7c009e7ed06119b00b6df5f689775e3305d077
+size 302310733