build(deps): Bump datadog from 0.34.1 to 0.35.0 in /backend (#456)

Bumps [datadog](https://github.com/DataDog/datadogpy) from 0.34.1 to 0.35.0.
- [Release notes](https://github.com/DataDog/datadogpy/releases)
- [Changelog](https://github.com/DataDog/datadogpy/blob/master/CHANGELOG.md)
- [Commits](DataDog/datadogpy@v0.34.1...v0.35.0)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

backend/requirements.txt

@@ -1,6 +1,6 @@
 -e ../tools #egg=code-coverage-tools
 connexion==2.6.0
-datadog==0.34.1
+datadog==0.35.0
 fakeredis==1.2.1
 Flask==1.1.1
 Flask-Cors==3.0.8