Add managedServerDnsAlias to readme file (#19224)

Co-authored-by: Stefan Krivokapic <[email protected]>

Author: krivi37

specification/sql/resource-manager/readme.md

@@ -278,6 +278,7 @@ input-file:
 - ./Microsoft.Sql/preview/2021-11-01-preview/BlobAuditing.json
 - ./Microsoft.Sql/preview/2021-11-01-preview/DatabaseAdvancedThreatProtectionSettings.json
 - ./Microsoft.Sql/preview/2021-11-01-preview/ServerAdvancedThreatProtectionSettings.json
+- ./Microsoft.Sql/preview/2021-11-01-preview/ManagedServerDnsAliases.json
 
 # Needed when there is more than one input file
 override-info: