Update ddtrace requirement from ~=1.9.4 to ~=2.1.4

Updates the requirements on [ddtrace](https://github.com/DataDog/dd-trace-py) to permit the latest version.
- [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@v1.9.4...v2.1.4)

---
updated-dependencies:
- dependency-name: ddtrace
  dependency-type: direct:production
...

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

requirements.txt

@@ -17,5 +17,5 @@ django-storages~=1.13
 gunicorn~=20.1.0
 psycopg2-binary~=2.9.5
 sentry-sdk~=1.28.1
-ddtrace~=1.9.4
+ddtrace~=2.1.4
 setproctitle~=1.3.2