- GHA release workflow is updated to use an action for uploading all assets. The
action docs say it updates a release if one already exists, and since this
triggers on release and we pass a release tag we know the release already
exists.
- GHA release candidate workflow is updated to auto-publish a pre-release
release on push to a `release/**` branch. A script is added and used to
generate a release message made up of the commits since the last release of
any kind.
- ACT profiles are added to allow locally testing these workflows without
needing to push and wait for GHA to run.
- Docs are updated to note how to test the workflows locally.
Joel Goguen