Support new stage RC 2 for 4.8.1 in wazuh-kubernetes repository

Description

This issue attempts to support a new stage RC 2 for 4.8.1 in the wazuh-kubernetes repository.

[x] Ensure changelog is updated for 4.8.1 (if applicable).
[x] Bump revision for branch 4.8.1 on wazuh-kubernetes repository.
[x] Change docker image tag in docker-compose to tag v4.8.1-rc2 in branch 4.8.1
[x] Create tag v4.8.1-rc2 from branch 4.8.1 on wazuh-kubernetes repository.
[x] Create and publish a pre-release: https://github.com/wazuh/wazuh-kubernetes/releases/tag/v4.8.1-rc2.
[x] Change docker image tag in docker-compose back to 4.8.1 in branch 4.8.1