Add github action to auto-publish crate when cargo.toml version is bumped.

[aburkhalter512]

[p0lunin]

Good idea. If you wish to implemet this feature, see example: https://github.com/cucumber-rs/cucumber/blob/v0.13.0/.github/workflows/ci.yml#L203-L271

[aburkhalter512]

I'll take a crack at it