Updates readme for 2.2 (#568)

# Description

Updates README with 2.2 version compatibility and removes mentions of
the feature isaacsim5.0 branch since that will be replaced by the
official 2.2 release.

## Type of change

- This change requires a documentation update

## Checklist

- [x] 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
- [ ] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

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README.md

@@ -143,20 +143,16 @@ Our [documentation page](https://isaac-sim.github.io/IsaacLab) provides everythi
 Isaac Lab is built on top of Isaac Sim and requires specific versions of Isaac Sim that are compatible with each release of Isaac Lab.
 Below, we outline the recent Isaac Lab releases and GitHub branches and their corresponding dependency versions for Isaac Sim.
 
-| Isaac Lab Version             | Isaac Sim Version |
-| ----------------------------- | ----------------- |
-| `main` branch                 | Isaac Sim 4.5     |
-| `v2.1.0`                      | Isaac Sim 4.5     |
-| `v2.0.2`                      | Isaac Sim 4.5     |
-| `v2.0.1`                      | Isaac Sim 4.5     |
-| `v2.0.0`                      | Isaac Sim 4.5     |
-| `feature/isaacsim_5_0` branch | Isaac Sim 5.0     |
-
-Note that the `feature/isaacsim_5_0` will contain active updates and may contain some breaking changes
-until the official Isaac Lab 2.2 release.
-It currently requires the [Isaac Sim 5.0 branch](https://github.com/isaac-sim/IsaacSim) available on GitHub built from source.
-Please refer to the README in the `feature/isaacsim_5_0` branch for instructions for using Isaac Lab with Isaac Sim 5.0.
-We are actively working on introducing backwards compatibility support for Isaac Sim 4.5 for this branch.
+| Isaac Lab Version             | Isaac Sim Version   |
+| ----------------------------- | ------------------- |
+| `main` branch                 | Isaac Sim 5.0       |
+| `v2.2.0`                      | Isaac Sim 4.5 / 5.0 |
+| `v2.1.1`                      | Isaac Sim 4.5       |
+| `v2.1.0`                      | Isaac Sim 4.5       |
+| `v2.0.2`                      | Isaac Sim 4.5       |
+| `v2.0.1`                      | Isaac Sim 4.5       |
+| `v2.0.0`                      | Isaac Sim 4.5       |
+| `feature/isaacsim_5_0` branch | Isaac Sim 4.5 / 5.0 |
 
 
 ## Contributing to Isaac Lab