[Docs] Add upgrade notes for the Incompatible authentication parameter

[swuferhong]

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Description

Since Fluss-0.8 changed the package name, when upgrading the server from 0.7 to 0.8, user need to modify security.sasl.enabled.mechanisms as follows:
origin:

new:

This change needs to be emphasized in the upgrade notes.

Willingness to contribute

• I'm willing to submit a PR!