Bumps [serde_json](https://github.com/serde-rs/json) from 1.0.60 to 1.0.61.
- [Release notes](https://github.com/serde-rs/json/releases)
- [Commits](https://github.com/serde-rs/json/compare/v1.0.60...v1.0.61)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* Bump versions

* Upgrade dependencies

* Update CHANGELOG.md

* Fix CHANGELOG.md

* Remove changelog messages about CI

* Extract contract metadata to its own crate

* Add json serialization test

* Add json test for excluding optional fields

* Add doc tests and rename to contract-metadata

* Fmt

* Fix tests

* Fmt

* Builder API for contract metadata

* Tests for builder pattern

* Fmt

* Make metadata version camel case

* Builder optional fields

* Check whether fields have not already been set

* Check at least one author

* I really should check it compiles before pushing

* Oh yeah and cargo fmt fml

* Yeah