poetry: bump datamodel-code-generator from 0.26.1 to 0.31.2

---
updated-dependencies:
- dependency-name: datamodel-code-generator
  dependency-version: 0.31.2
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]