Include observation.environment_state with keypoints in PushT dataset (#303)

Co-authored-by: Remi <re.cadene@gmail.com>

lerobot/scripts/push_dataset_to_hub.py

@@ -40,6 +40,60 @@ python lerobot/scripts/push_dataset_to_hub.py \
 --raw-format umi_zarr \
 --repo-id lerobot/umi_cup_in_the_wild
 ```
+
+**WARNING: Updating an existing dataset**
+
+If you want to update an existing dataset, you need to change the `CODEBASE_VERSION` from `lerobot_dataset.py`
+before running `push_dataset_to_hub.py`. This is especially useful if you introduce a breaking change
+intentionally or not (i.e. something not backward compatible such as modifying the reward functions used,
+deleting some frames at the end of an episode, etc.). That way, people running a previous version of the
+codebase won't be affected by your change and backward compatibility is maintained.
+
+For instance, Pusht has many versions to maintain backward compatibility between LeRobot codebase versions:
+- [v1.0](https://huggingface.co/datasets/lerobot/pusht/tree/v1.0)
+- [v1.1](https://huggingface.co/datasets/lerobot/pusht/tree/v1.1)
+- [v1.2](https://huggingface.co/datasets/lerobot/pusht/tree/v1.2)
+- [v1.3](https://huggingface.co/datasets/lerobot/pusht/tree/v1.3)
+- [v1.4](https://huggingface.co/datasets/lerobot/pusht/tree/v1.4)
+- [v1.5](https://huggingface.co/datasets/lerobot/pusht/tree/v1.5) <-- last version
+- [main](https://huggingface.co/datasets/lerobot/pusht/tree/main)  <-- points to the last version
+
+However, you will need to update the version of ALL the other datasets so that they have the new
+`CODEBASE_VERSION` as a branch in their hugging face dataset repository. Don't worry, there is an easy way
+that doesn't require to run `push_dataset_to_hub.py`. You can just "branch-out" from the `main` branch on HF
+dataset repo by running this script which corresponds to a `git checkout -b` (so no copy or upload needed):
+
+```python
+import os
+
+from huggingface_hub import create_branch, hf_hub_download
+from huggingface_hub.utils._errors import RepositoryNotFoundError
+
+from lerobot import available_datasets
+from lerobot.common.datasets.lerobot_dataset import CODEBASE_VERSION
+
+os.environ["HF_HUB_DISABLE_PROGRESS_BARS"] = "1"  # makes it easier to see the print-out below
+
+NEW_CODEBASE_VERSION = "v1.5"  # REPLACE THIS WITH YOUR DESIRED VERSION
+
+for repo_id in available_datasets:
+    # First check if the newer version already exists.
+    try:
+        hf_hub_download(
+            repo_id=repo_id, repo_type="dataset", filename=".gitattributes", revision=NEW_CODEBASE_VERSION
+        )
+        print(f"Found existing branch for {repo_id}. Please contact a member of the core LeRobot team.")
+        print("Exiting early")
+        break
+    except RepositoryNotFoundError:
+        # Now create a branch.
+        create_branch(repo_id, repo_type="dataset", branch=NEW_CODEBASE_VERSION, revision=CODEBASE_VERSION)
+        print(f"{repo_id} successfully updated")
+
+```
+
+On the other hand, if you are pushing a new dataset, you don't need to worry about any of the instructions
+above, nor to be compatible with previous codebase versions.
 """
 
 import argparse
@@ -317,7 +371,10 @@ def main():
     parser.add_argument(
         "--tests-data-dir",
         type=Path,
-        help="When provided, save tests artifacts into the given directory for (e.g. `--tests-data-dir tests/data/lerobot/pusht`).",
+        help=(
+            "When provided, save tests artifacts into the given directory "
+            "(e.g. `--tests-data-dir tests/data` will save to tests/data/{--repo-id})."
+        ),
     )
 
     args = parser.parse_args()