package/redis: security bump to v6.0.12

package/redis: security bump to v6.0.12

From the release notes:
(https://github.com/redis/redis/blob/6.0.12/00-RELEASENOTES)

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Redis 6.0.11     Released Mon Feb 22 16:13:23 IST 2021
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Upgrade urgency: SECURITY if you use 32bit build of redis (see bellow), LOW
otherwise.

Integer overflow on 32-bit systems (CVE-2021-21309):
Redis 4.0 or newer uses a configurable limit for the maximum supported bulk
input size. By default, it is 512MB which is a safe value for all platforms.
If the limit is significantly increased, receiving a large request from a client
may trigger several integer overflow scenarios, which would result with buffer
overflow and heap corruption.

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Redis 6.0.12     Released Mon Mar  1 17:29:52 IST 2021
================================================================================

Upgrade urgency: LOW, fixes a compilation issue.

Bug fixes:
* Fix compilation error on non-glibc systems if jemalloc is not used (#8533)

Signed-off-by: Titouan Christophe <titouanchristophe@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>