Bump ddtrace from 2.1.2 to 2.1.3

Bumps [ddtrace](https://github.com/DataDog/dd-trace-py) from 2.1.2 to 2.1.3.
- [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@v2.1.2...v2.1.3)

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

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