Bump redis dependency to 4.0.2

[sarah-witt]

What does this PR do?

Bumps redis dependency to 4.0.2

Motivation

• Include fix for AttributeError: 'Redis' object has no attribute 'sentinel_masters' redis/redis-py#1714
• The redis sentinel integration relies on the functionality broken in 4.0.1, which was bumped recently

Additional Notes

• No other major changes were released in 4.0.2:

* 4.0.2 (Nov 22, 2021)
    * Restoring Sentinel commands to redis client (#1723)
    * Better removal of hiredis warning (#1726)
    * Adding links to redis documents in function calls (#1719)

• Reproduced by installing redis sentinel integration, then verified the fix by manually bumping redis to 4.0.2 in the agent and running the redis sentinel integration successfully

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached