[0.5 release] Update version references for release

Author: SS-JIA

docs/source/getting-started-setup.md

@@ -80,9 +80,7 @@ Alternatively, if you would like to experiment with ExecuTorch quickly and easil
 
    ```bash
    # Clone the ExecuTorch repo from GitHub
-   # 'main' branch is the primary development branch where you see the latest changes.
-   # 'viable/strict' contains all of the commits on main that pass all of the necessary CI checks.
-   git clone --branch viable/strict https://github.com/pytorch/executorch.git
+   git clone --branch release/0.5 https://github.com/pytorch/executorch.git
    cd executorch
 
    # Update and pull submodules

pyproject.toml

@@ -68,6 +68,9 @@ dependencies=[
   "ruamel.yaml",
   "sympy",
   "tabulate",
+  "torch==2.6.0",
+  "torchaudio==2.6.0",
+  "torchvision==0.21.0",
   "typing-extensions",
 ]