docs: add note for upgrade workaround (#1598)

Author: MemberIT

charts/sentry/CHANGELOG.md

@@ -43,6 +43,8 @@
 
 Make sure to upgrade to chart version 25.20.0 (Seentry 24.8.0) before upgrading to 26.x.x
 
+**Note:** In version [sentry-v25.19.0](https://github.com/sentry-kubernetes/charts/releases/tag/sentry-v26.5.0) ([commit](https://github.com/sentry-kubernetes/charts/commit/f5a12e04ee5ffa28f1d62bf6c7cb5c733b30c2b9)), SASL authentication functionality for Kafka was added, which broke backward compatibility when using an external Kafka cluster. The single-host external kafka setup works correctly. The [issue #1584](https://github.com/sentry-kubernetes/charts/issues/1584) was fixed in version [sentry-v26.5.0](https://github.com/sentry-kubernetes/charts/releases/tag/sentry-v26.5.0) ([commit](https://github.com/sentry-kubernetes/charts/commit/889bd0d47235cb1ab5a7b52439f5b8df61026a03)). In this case, for a sequential upgrade, a viable workaround could be to use [sentry-v26.5.0](https://github.com/sentry-kubernetes/charts/releases/tag/sentry-v26.5.0) with `appVersion: 24.8.0` initially ([Chart.yml](https://github.com/sentry-kubernetes/charts/blob/sentry-v26.5.0/charts/sentry/Chart.yaml#L6)), and then use [sentry-v26.5.0](https://github.com/sentry-kubernetes/charts/releases/tag/sentry-v26.5.0) as is ([details](https://github.com/sentry-kubernetes/charts/pull/1588#issuecomment-2459117235)).
+
 ### Features
 
 * add maxTasksPerChild option to Sentry worker deployments ([#1572](https://github.com/sentry-kubernetes/charts/issues/1572)) ([bc32900](https://github.com/sentry-kubernetes/charts/commit/bc329004f46f4af7ecf4a99f07e74e28dbee436e))