Add `agent.pt` and tag the environment

This commit adds a model that is compatible with the 🥇 [Open RL Leaderboard](https://huggingface.co/spaces/open-rl-leaderboard/leaderboard) 🥇.

README.md

@@ -5,6 +5,7 @@ tags:
 - deep-reinforcement-learning
 - reinforcement-learning
 - stable-baselines3
+- Hopper-v4
 model-index:
 - name: TD3
   results:

agent.pt

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:fe1573404ca42f928c126d5f9f3120c3fd3ad62d0bba3339d4310b689a2c8b0c
-size 508129
+oid sha256:117eaee66c620e84c817d59ef145fe880c9f1bf0d543fe0558851557e414f4fb
+size 508173