fix: update release note for aks-preview 14.0.0b6 (#8707)

Author: nddq

src/aks-preview/HISTORY.rst

@@ -11,6 +11,9 @@ To release a new version, please select a new version number (usually plus 1 to
 
 Pending
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+14.0.0b6
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 * Add option `--acns-advanced-networkpolicies <None|FQDN|L7>` to `az aks create/update`
 
 14.0.0b5