build(deps-dev): update unleashclient requirement from <6 to <7

Updates the requirements on [unleashclient](https://github.com/Unleash/unleash-python-sdk) to permit the latest version.
- [Release notes](https://github.com/Unleash/unleash-python-sdk/releases)
- [Changelog](https://github.com/Unleash/unleash-python-sdk/blob/main/CHANGELOG.md)
- [Commits](https://github.com/Unleash/unleash-python-sdk/commits/v6.7.0)

---
updated-dependencies:
- dependency-name: unleashclient
  dependency-version: 6.7.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

pyproject.toml

@@ -60,7 +60,7 @@ typing = [
     "launchdarkly-server-sdk",
     "openfeature-sdk",
     "statsig",
-    "UnleashClient<6",
+    "UnleashClient<7",
     "typer",
     "strawberry-graphql",
     "httpx",