Compatibility with the latest setuptools

[frenzymadness]

With setuptools 62.1 and newer, it's not possible to build this package. The error says:

error: Multiple top-level packages discovered in a flat-layout: ['etc', 'agent', 'packaging'].

To avoid accidental inclusion of unwanted files or directories,
setuptools will not proceed with this build.

If you are trying to create a single distribution with multiple packages
on purpose, you should not rely on automatic discovery.
Instead, consider the following options:

1. set up custom discovery (`find` directive with `include` or `exclude`)
2. use a `src-layout`
3. explicitly set `py_modules` or `packages` with a list of names

To find more information, look for "package discovery" on setuptools docs.

[ekodikara]

Workaround - do it manually.

sudo install -m 0755 agent/hibinit-agent /usr/local/bin/hibinit-agent
sudo install -m 0644 etc/hibinit-config.cfg /etc/hibinit-config.cfg

Test:

which hibinit-agent
hibinit-agent --help

If you see this cannot execute: required file not found
Try this:

sudo sed -i '1s|^#!.*|#!/usr/bin/env python3|' /usr/local/bin/hibinit-agent

And test again.

(Optional) Enable at Boot via systemd

# /etc/systemd/system/hibinit-agent.service
[Unit]
Description=Amazon EC2 Hibernation Agent

[Service]
ExecStart=/usr/local/bin/hibinit-agent
Restart=on-failure

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reexec
sudo systemctl daemon-reload
sudo systemctl enable hibinit-agent
sudo systemctl start hibinit-agent