Release PR for 0.4.2 (#226)

<!---
Include the number of the issue addressed by this PR above if
applicable.
  PRs for code changes without an associated issue *will not be merged*.
  See CONTRIBUTING.md for more information.
-->

### Description
Release PR for 0.4.2. Includes,
- Datepart bug fix
- conversion metric spec additions and validations

<!---
Describe the Pull Request here. Add any references and info to help
reviewers
  understand your changes. Include any tradeoffs you considered.
-->

### Checklist

- [x] I have read [the contributing
guide](https://github.com/dbt-labs/dbt-semantic-interfaces/blob/main/CONTRIBUTING.md)
and understand what's expected of me
- [x] I have signed the
[CLA](https://docs.getdbt.com/docs/contributor-license-agreements)
- [x] This PR includes tests, or tests are not required/relevant for
this PR
- [x] I have run `changie new` to [create a changelog
entry](https://github.com/dbt-labs/dbt-semantic-interfaces/blob/main/CONTRIBUTING.md#adding-a-changelog-entry)

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "dbt-semantic-interfaces"
-version = "0.4.2.dev0"
+version = "0.4.2"
 description = 'The shared semantic layer definitions that dbt-core and MetricFlow use'
 readme = "README.md"
 requires-python = ">=3.8"