Provide example of file based package install. (#1424)
Added example to install packages from a file w/o editable mode.
I use `pip install .` in a number of CI/CD and build scripts - it wasn't
obvious to me how to achieve this with uv as `uv pip install .` throws
an error about package names being expected to start with an
alphanumeric character.
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Co-authored-by: Zanie Blue <contact@zanie.dev>
