documentation: mentions pipx requires python-3.7+ while 3.8+ is supported

[MrLixm]

Describe the bug

Hello,
The documentation mentions that pipx support python 3.7 and above:

pipx/docs/installation.md

Lines 3 to 4 in 543af21

	python 3.7+ is required to install pipx. pipx can run binaries from packages with Python 3.3+. Don't have Python 3.7 or
	later? See [Python 3 Installation & Setup Guide](https://realpython.com/installing-python/).

However the pyproject indicates it only supports 3.8+:

pipx/pyproject.toml

Line 23 in 543af21

requires-python = ">=3.8"

Expected behavior

The documentation correctly specifies the minimal python version required to install pipx.

Additional links

• related to Drop Python 3.7 #1005

---

Thanks !
Liam.