Motivation:
We have upgraded cron-utils to 9.2.1 to address [CVE-2021-41269](GHSA-p9m8-27x8-rg87).
The 9.2.1 version uses slf4j2 that must be used with logback 1.3 or 1.4.
Because we use logback 1.2 version in Armeria, we need to exclude slf4j2: line#872
Just excluding slf4j should be okay because cron-utils isn't using any APIs that are introduced after slf4j 2.0:
https://github.com/search?q=repo%3Ajmrozanec%2Fcron-utils+slf4j&type=code
However, there's no guarantee that cron-utils won't use the new APIs in the future.
So, I think we should stop upgrading it until there's another CVE is found or Armeria uses higher version of Logback and Slf4j.\

While, I'm working on this I found out that cron-utils 9.2.0, which is one micro version eariler, uses Slf4j 1.x which is compatible with Armeria
so it's better to use that version.

Modification:
- Downgrade cron-utils to 9.2.0

Result:
- Resovle dependency conflict for server module.