Set up automated update of packed tz data

[neoeinstein]

With the goal of keeping the crate's packed tz data up to date, we should consider setting up an automated system that will publish a new version (possibly using the build metadata field instead of incrementing the patch version) whenever the tz repository is updated.

i am willing to work on writing up a job that can make this functional and/or doing the initial manual upkeep.

[quodlibetor]

This is a great idea! What kind of automated system were you imagining?

[neoeinstein]

It's been a while, but I saw that this had partially been done now with a Github action. That action is broken at the moment, but I've submitted #79 to fix it again. I'd be happy to assist in getting more regular deployments going again (I see that the latest PRs haven't been merged or published), so that when the TZ update PR is merged, it gets pushed out to crates.io.

[pitdicker]

The GitHub Action was broken again and removed in #159. From that PR:

Because we need to check the changes anyway to see if they would be a breaking change, and we manually have to increase the version number of chrono-tz and publish a release, I don't think this action gives much benefit.