Groovy utf-8 encoding JSON or CSV file

I’m beginner in Groovy, I do JSON parsing and export data to a csv file, but it turns out like in the screenshot. How can I better write it in the code so that the data is correct when exporting to a file, or do I need to convert the csv file itself to UTF-8?

import groovy.json.JsonSlurper 
def conn = "http://jira.server.net:8080/rest/api/2/project/".toURL().openConnection()
conn.setRequestProperty('Authorization', 'Basic ' + 'login:password'.bytes.encodeBase64().toString())
 if(conn.responseCode == 200) {
     def jsonSlurper = new JsonSlurper()
     def data = jsonSlurper.parseText(conn.content.text)

     def file = new File("C:/Temp/data.csv")

     def stringBuilder = new StringBuilder()
     data.each { row ->
         stringBuilder.append(row.join(';')).append(System.lineSeparator())
               }

     file.text = stringBuilder.toString()
 } else {
     println "Something bad happened."
     println "${conn.responseCode}: ${conn.responseMessage}"
 }

Result:

Разработка СПО ПТСПК версии