Add alternative to pip3 install of cargo lambda

When running `pip3 install .....` it shows this error about system vs user installation:

```
rror: externally-managed-environment

× This environment is externally managed
╰─> To install Python packages system-wide, try apt install
    python3-xyz, where xyz is the package you are trying to
    install.
    
    If you wish to install a non-Debian-packaged Python package,
    create a virtual environment using python3 -m venv path/to/venv.
    Then use path/to/venv/bin/python and path/to/venv/bin/pip. Make
    sure you have python3-full installed.
    
    If you wish to install a non-Debian packaged Python application,
    it may be easiest to use pipx install xyz, which will manage a
    virtual environment for you. Make sure you have pipx installed.
    
    See /usr/share/doc/python3.12/README.venv for more information.

```

Another way to manage executable pip packages is with uv which has been very popular and helpful in the python community.

```

Author: Bryson14

README.md

@@ -37,6 +37,11 @@ Or PiP on any system with Python 3 installed:
 ```bash
 pip3 install cargo-lambda
 ```
+Alternative, install the pip package as an executable using [uv](https://docs.astral.sh/uv/)
+
+```bash
+uv tool install cargo-lambda
+```
 
 See other installation options in [the Cargo Lambda documentation](https://www.cargo-lambda.info/guide/installation.html).