[7.x] [Kibana Plugin Generator]target branch → version (#3020… (#41516)

A version error will occur each time the following procedure is executed.
Changing「6.6」 from 「6.6.1」 will succeed.
So I changed branch (6.6) to version(6.6.1).

1.Execute「node scripts/generate_plugin my_plugin_name」with [Kibana Plugin Generator][Quick Start]
2.Answer「6.6」to the question 「What Kibana version are you targeting?（6.x）」
3.Execute「yarn start」

packages/kbn-plugin-generator/sao_template/sao.js

@@ -40,7 +40,7 @@ module.exports = function({ name }) {
       },
       kbnVersion: {
         message: 'What Kibana version are you targeting?',
-        default: kibanaPkg.branch,
+        default: kibanaPkg.version,
       },
       generateApp: {
         type: 'confirm',