Release 0.29.0

[Mingun]

Checklist (minimal list of actions for cutting release):

• Merge Implement write_serializable_content on element writer #508?
• $env:RUSTDOCFLAGS="--cfg docs_rs"; cargo +nightly doc --all-features and check generated documentation for missing / unclear things
• Update version in Cargo.toml
• Update Changelog.md with date of release, add new empty Unreleased headings
• cargo package for final check
• Push master to my fork, wait while CI pass. Repeat with force pushs if necessary
• cargo publish
• Create and push tag v0.29.0 and push master to upstream
• Create a Release on GitHub (in GitHub UI)

[dralley]

#508 is a feature, I would expect it would go into 0.29

[Mingun]

Yes, it is. Actually, semver allows as release either 0.28.3 or 0.29.0. I just thinking, that because we have not breaking changes in current master and in #508, we could do a patch release (the previous 0.28.1 and 0.28.2 I'd made with the same rationale). But if you insist, lets release as 0.29.0

[dralley]

That's not my understanding of semver, my understanding is that patch releases are for bugfixes rather than functionality. I don't care much though.

[Mingun]

Because I just merged #612 which adds new Error variant, now the target version will be 0.29.0.

@dralley, I plan to make release tomorrow, approximately 15-20 hours later. So if you have time to finish with #609 before that time -- OK. No - well, okay, will be included in the next release

[dralley]

I won't have time, I have some items at work to deal with first. It's fine to put it in the next release.