small tweaks

CONTRIBUTING.md

@@ -139,11 +139,13 @@ Follow these steps to start contributing:
 
    To develop on 🤗 LeRobot, you will at least need to install the `dev` and `test` extras dependencies along with the core library:
    ```bash
+   pip install poetry
    poetry install --sync --extras "dev test"
    ```
 
    You can also install the project with all its dependencies (including environments):
    ```bash
+   pip install poetry
    poetry install --sync --all-extras
    ```
 

lerobot/common/logger.py

@@ -84,7 +84,11 @@ class Logger:
             if self._wandb and not self._disable_wandb_artifact:
                 # note wandb artifact does not accept ":" in its name
                 artifact = self._wandb.Artifact(
-                    self._group.replace(":", "_") + "-" + str(self._seed) + "-" + str(identifier),
+                    self._group.replace(":", "_").replace("/", "__")
+                    + "-"
+                    + str(self._seed)
+                    + "-"
+                    + str(identifier),
                     type="model",
                 )
                 artifact.add_file(save_dir / SAFETENSORS_SINGLE_FILE)