Add Release pipeline

[umbynos]

This PR adds the release pipeline that will be used to build avrdude as static as possible for the platforms we need.
The CI does basically 3 things:

• Pull the upstream repo from avrdudes, patch it, and crosscompile the source code, and prepare the packaging
• notarize the macOS binary
• release on GitHub and on download servers, generating the snippet for the package_index.json

This repository contains only the release pipeline and the patches that we need to apply on top of it. I hope that we will be able to upstream them, as soon this PR is merged and the repo gets moved under arduino GitHub organization and made public.

The tag mechanism is a bit peculiar, but IMHO is the best we can do. It should be formatted like this <AVRDUDE_TAG>-arduino.<ARDUINO_VERSION>, an example tag is 7.0-arduino.1. The AVRDUDE_TAG represents the tag avdude tag to checkout, while ARDUINO_VERSION allows us to make some modifications and still be able to release, using the same avrdude tag as a starting point.

An example release can be found here

[per1234]

@umbynos would you mind triggering another test release for the sake of getting an automated validation on the changes made via the PR review suggestions?

[umbynos]

https://github.com/bcmi-labs/avdude-packing/releases/tag/7.0-arduino.1

[per1234]

Excellent work Umberto. Thanks!

[umbynos]

Test release removed