The "Joomla packager" is github tool that will easily take your joomla extension source code and package it into an installable file, complete with changelog and updater. Here's a sample of its output.
Designed to handle components, modules, plugins or complete packages.
It's available either as a single large workflow or a "smart" github action.
In its "action" form it natively uses the repo information to determine most of its settings. Each can be easily overridden however.
In its "workflow" form there is a configuration section at the top of the workflow file to determine what it does.
I've attempted to document each setting and its behavior throughout this documentation.