Update redis requirement from >=2.10.5,<3.0.0 to >=2.10.5,<6.0.0

Updates the requirements on [redis](https://github.com/redis/redis-py) to permit the latest version.
- [Release notes](https://github.com/redis/redis-py/releases)
- [Changelog](https://github.com/redis/redis-py/blob/master/CHANGES)
- [Commits](redis/redis-py@2.10.5...v5.0.1)

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

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

Author: dependabot[bot]

pyproject.toml

@@ -51,7 +51,7 @@ test-filesource = ["pyyaml", "watchdog"]
 [tool.poetry.group.dev.dependencies]
 mock = ">=2.0.0"
 pytest = ">=2.8"
-redis = ">=2.10.5,<3.0.0"
+redis = ">=2.10.5,<6.0.0"
 boto3 = ">=1.9.71,<2.0.0"
 coverage = ">=4.4"
 jsonpickle = ">1.4.1"