Bump ddtrace from 1.19.0 to 1.20.0

Bumps [ddtrace](https://github.com/DataDog/dd-trace-py) from 1.19.0 to 1.20.0.
- [Release notes](https://github.com/DataDog/dd-trace-py/releases)
- [Changelog](https://github.com/DataDog/dd-trace-py/blob/2.x/CHANGELOG.md)
- [Commits](DataDog/dd-trace-py@v1.19.0...v1.20.0)

---
updated-dependencies:
- dependency-name: ddtrace
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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