build(deps): bump datadog from 0.42.0 to 0.43.0 in /backend

Bumps [datadog](https://github.com/DataDog/datadogpy) from 0.42.0 to 0.43.0.
- [Release notes](https://github.com/DataDog/datadogpy/releases)
- [Changelog](https://github.com/DataDog/datadogpy/blob/master/CHANGELOG.md)
- [Commits](DataDog/datadogpy@v0.42.0...v0.43.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

backend/requirements.txt

@@ -1,6 +1,6 @@
 -e ../tools #egg=code-coverage-tools
 connexion==2.9.0
-datadog==0.42.0
+datadog==0.43.0
 fakeredis==1.7.0
 Flask==1.1.2
 Flask-Cors==3.0.10