docs: README.md: Add pipx installation and run instructions (#165)

README.md

@@ -5,3 +5,26 @@ Documents are available at [gyp.gsrc.io](https://gyp.gsrc.io), or you can check
 
 __gyp-next__ is [released](https://github.com/nodejs/gyp-next/releases) to the [__Python Packaging Index__](https://pypi.org/project/gyp-next) (PyPI) and can be installed with the command:
 * `python3 -m pip install gyp-next`
+
+When used as a command line utility, __gyp-next__ can also be installed with [pipx](https://pypa.github.io/pipx):
+* `pipx install gyp-next`
+```
+Installing to a new venv 'gyp-next'
+  installed package gyp-next 0.13.0, installed using Python 3.10.6
+  These apps are now globally available
+    - gyp
+done! ✨ 🌟 ✨
+```
+
+Or to run __gyp-next__ directly without installing it:
+* `pipx run gyp-next --help`
+```
+NOTE: running app 'gyp' from 'gyp-next'
+usage: usage: gyp [options ...] [build_file ...]
+
+options:
+  -h, --help            show this help message and exit
+  --build CONFIGS       configuration for build after project generation
+  --check               check format of gyp files
+  [ ... ]
+```