Update minor version to 9.1.0 (#24549)

Automatic Merge

server/public/model/version.go

@@ -13,6 +13,7 @@ import (
 // It should be maintained in chronological order with most current
 // release at the front of the list.
 var versions = []string{
+	"9.1.0",
 	"9.0.0",
 	"8.1.0",
 	"8.0.0",