Add v2.0.0 breaking changes on python environment names and RSL-RL package rename (#1890)

# Description

Partially addresses issue:
https://github.com/isaac-sim/IsaacLab/issues/1840

The [v2.0.0 release
notes](https://github.com/isaac-sim/IsaacLab/releases/tag/v2.0.0) on
GitHub should also be modified accordingly.

Although this PR doesn't fix the RSL-RL package name change for Isaac
Lab v1.4.1 and earlier versions, listing this change in the release
notes would be better.

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [ ] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

---------
Signed-off-by: Mayank Mittal <12863862+Mayankm96@users.noreply.github.com>
Co-authored-by: Mayank Mittal <12863862+Mayankm96@users.noreply.github.com>

docs/source/refs/release_notes.rst

@@ -78,6 +78,8 @@ Breaking Changes
 * Updates the URDF and MJCF importers for Isaac Sim 4.5 by @Dhoeller19
 * Renames Isaac Lab extensions and folders by @kellyguo11
 * Restructures extension folders and removes old imitation learning scripts by @kellyguo11
+* Renames conda and venv Python environment from ``isaaclab`` to ``env_isaaclab`` by @Toni-SM
+* Fixes RSL-RL package name in `setup.py` according to PyPI installation by @samibouziri
 
 Migration Guide
 ---------------