chore: Automate Release Pipeline || Test Token Update

[deepakraog]

Automate Release Pipeline - publishing releases to cargo #93

[aesterline]

Is this line necessary? Olaf and I thought that if it isn't present, the release process will do the right thing.

[tommy]

I'd be interested for us to try using https://release-plz.ieni.dev/docs

It is a flow similar to Google's release-please, which we've used in other repos for mostly Typescript libraries. The basic flow is:

• a release PR is automatically opened on the first commit since the previous release. The bot workflow keeps it up-to-date with all the unreleased changes.
• it contains the Cargo.toml version bump, plus maintains a changelog file.
• when a developer (with write access) is ready to release, they merge that PR
• a workflow runs which tags and publishes that commit.

Since all of our repos disallow direct pushes to the main branch, this "release PR" approach is a convenient way to meet that requirement.

(As an added bonus, this project uses cargo semver-checks to look for backwards-incompatible API changes.)

(Github actions instructions here: https://release-plz.ieni.dev/docs/github/quickstart)