Bump poem from 2.0.1 to 3.1.6

Bumps [poem](https://github.com/poem-web/poem) from 2.0.1 to 3.1.6.
- [Release notes](https://github.com/poem-web/poem/releases)
- [Commits](https://github.com/poem-web/poem/commits)

---
updated-dependencies:
- dependency-name: poem
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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