Simplify example invocation in README

[pinch] / Changelog

## [Unreleased]
- Fix a bash-ism in test.sh, which is #!/bin/sh
- Fix setup.py package description
- Simplify example invocation in README


## [3.0.14] - 2024-01-24
- Allow identical broken symlinks


## [3.0.13] - 2023-12-07
- Fixed nested-git issues in pre-commit hook
- Adapt to new, stricter minidom type checks
- Cleaned up changelog


## [3.0.12] - 2023-09-07
- Show which files are unexpectedly incomparable
- Allow nixpkgs' new intentionally-invalid symlink


## [3.0.11] - 2023-05-24
- Specify license
- Dropped "pylint: disable=no-self-use"
- Adapt to nixpkgs nativeCheckInputs change


## [3.0.10] - 2022-11-23
- Small cleanups


## [3.0.9] - 2022-04-16
- Really fix tests after restricted mode support update, whether or not the user has channels.


## [3.0.8] - 2022-04-15
- Fix tests after restricted mode support update (Actually: break them worse)
- Fix git-cache fetch URL


## [3.0.7] - 2022-02-01
- Don't leave old channels laying around


## [3.0.6] - 2022-01-19
- Deprecate pinch.
- Show the channel URL being fetched.
- Use nix 2.3 because 2.4 broke <nix/unpack-channel.nix>.
- Support restricted mode: Allow tarball and manifest access with search paths.
- Announce test names as they are run.


## [3.0.5] - 2021-07-09
- Show filename being hashed.  Helps find nix store corruption.


## [3.0.4] - 2021-06-07
- Use nix from nixpkgs rather than from PATH.  This is needed when the nix in
PATH is nixUnstable-3.0pre20201020_e0ca98c or later because nix commit
787469c7b66aec12ab6847e7db2cdc8aef5c325e removed <nix/unpack-channel.nix>.


## [3.0.3] - 2021-05-20
- Don't pass --experimental-features to old nix versions


## [3.0.2] - 2021-02-16
- Don't rely on experimental-features=nix-command in system nix.conf


## [3.0.1] - 2020-08-04
- Make tests fast again when using recent git-cache with backoff


## [3.0.0] - 2020-07-10
- Moved git cache out to a separate library


## [2.1.1] - 2020-07-01
- Pin faster: Skip archive comparison if git rev is unchanged


## [2.1.0] - 2020-06-30
- Allow specifying profile path with --profile


## [2.0.0] - 2020-06-17
- Config sections must now specify their type explicitly
- Added type=symlink search paths


## [1.5.1] - 2020-06-17
- Support old mypy version 0.701 (by working around its bugs)
- Version numbers are now semver


## [1.5] - 2020-06-12
- Support log.showSignature


## [1.4] - 2020-06-11
First usable version