Motivation
* Following [GitHub's
announcement](https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/),
Node 20 is being deprecated and runners will begin using Node 24 by
default starting March 4th, 2026. Node 20 will reach end-of-life in
April 2026.
Modifications
* Upgrade GitHub Actions to their latest versions to ensure
compatibility with Node 24.
* Replace `actions/checkout@v4` with `actions/checkout@v6` in all
workflow files.
Result
* Workflow files reference `actions/checkout@v6`.
Motivation:
* More secure GitHub Actions workflows
Modifications:
Add explicit 'contents: read' permissions to workflows that did not have
explicit permissions defined. This follows GitHub Actions security best
practices by limiting the default GITHUB_TOKEN permissions.
Result:
An extra layer of security.
Migrate CI to use GitHub Actions.
### Motivation:
To migrate to GitHub actions and centralised infrastructure.
### Modifications:
Changes of note:
* Adopt swiftlang soundness checks, swift version matrix
* Remove scripts and docker files which are no longer needed
### Result:
Feature parity with old CI.
### Test Plan
Execute CI
Rick Newton-Rogers