build(deps-dev): bump datamodel-code-generator from 0.13.5 to 0.20.0

Bumps [datamodel-code-generator](https://github.com/koxudaxi/datamodel-code-generator) from 0.13.5 to 0.20.0.
- [Release notes](https://github.com/koxudaxi/datamodel-code-generator/releases)
- [Commits](koxudaxi/datamodel-code-generator@0.13.5...0.20.0)

---
updated-dependencies:
- dependency-name: datamodel-code-generator
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>