Bump notifications-python-client from 8.2.0 to 9.0.0

Bumps [notifications-python-client](https://github.com/alphagov/notifications-python-client) from 8.2.0 to 9.0.0.
- [Changelog](https://github.com/alphagov/notifications-python-client/blob/main/CHANGELOG.md)
- [Commits](https://github.com/alphagov/notifications-python-client/compare/8.2.0...9.0.0)

---
updated-dependencies:
- dependency-name: notifications-python-client
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

pyproject.toml

@@ -39,7 +39,7 @@ lxml = "==5.1.0"
 marshmallow = "==3.20.2"
 marshmallow-sqlalchemy = "==0.30.0"
 newrelic = "*"
-notifications-python-client = "==8.2.0"
+notifications-python-client = "==9.0.0"
 notifications-utils = {git = "https://github.com/GSA/notifications-utils.git"}
 oscrypto = "==1.3.0"
 packaging = "==23.2"