Release version 0.31

[alamb]

Filing a ticket here to track the work of a release (mostly so others can follow along)

Release instructions: https://github.com/sqlparser-rs/sqlparser-rs/blob/main/docs/releasing.md

Steps:

• Make a PR to update changelog
• run cargo publish

[alamb]

cc @AugustoFKL and @ankrgyl -- I plan to collect up what we have so far and publish a new release.

[alamb]

And we have a release 🎉 https://crates.io/crates/sqlparser/0.31.0

[alamb]

Will track next release in #821