Update using-executorch-ios.md (#10448)

Co-authored-by: Anthony Shoumikhin <[email protected]>

Author: pytorchbot

docs/source/using-executorch-ios.md

@@ -97,25 +97,25 @@ xcode-select --install
 2. Clone ExecuTorch:
 
 ```bash
-git clone -b release/0.6 https://github.com/pytorch/executorch.git && cd executorch
+git clone -b release/0.6 https://github.com/pytorch/executorch.git --depth 1 --recurse-submodules --shallow-submodules && cd executorch
 ```
 
 3. Set up [Python](https://www.python.org/downloads/macos/) 3.10+ and activate a virtual environment:
 
 ```bash
-python3 -m venv .venv && source .venv/bin/activate && ./install_requirements.sh
+python3 -m venv .venv && source .venv/bin/activate && pip install --upgrade pip
 ```
 
-4. Install the required dependencies, including those needed for the backends like [Core ML](backends-coreml.md) or [MPS](backends-mps.md). Choose one, or both:
+4. Install the required dependencies, including those needed for the backends like [Core ML](backends-coreml.md) or [MPS](backends-mps.md), if you plan to build them later:
 
 ```bash
-# ExecuTorch with xnnpack and CoreML backend
+./install_requirements.sh
+
+# CoreML-only requirements:
 ./backends/apple/coreml/scripts/install_requirements.sh
-./install_executorch.sh --pybind coreml xnnpack
 
-# ExecuTorch with xnnpack and MPS backend
+# MPS-only requirements:
 ./backends/apple/mps/install_requirements.sh
-./install_executorch.sh --pybind mps xnnpack
 ```
 
 5. Install [CMake](https://cmake.org):