* Initial version of release workflow using GitHub Actions
Add release workflow using GitHub Actions to replace the current Azure
DevOps pipeline. Currently the same functionality is implemented. This
uses multiple builds in parallel to make better use of CPU resources.
Remove Azure DevOps pipeline.
* Add GitHub Actions workflow for pull-request checks
Lint Dockerfile and shell scripts when PRs are opened.
* Use multiple runners in parallel
Buildroot has stretches where CPU resources are not fully utilized.
Spawn multiple builds accross builders to increase load. Also sort them
by architecture to maximize ccache hit rate.
* Checkout before validate version
* Change titels to reflect official/new naming
* Use GitHub Actions to trigger Release Drafter
The Add-On is no longer developed and GitHub Actions is the recommended
way to use the Release Drafter
