Werk #13308: Update redis to 6.2.6

Component	Other components
Title	Update redis to 6.2.6
Date	Oct 5, 2021
Level	Trivial Change
Class	Bug Fix
Compatibility	Compatible - no manual interaction needed
Checkmk versions & editions	2.1.0b1 Checkmk Community, Checkmk Pro, Checkmk Ultimate MT

To the list of all Werks