gistfile1.txt

@NonCPS
def call(String repository, String credentials) {
    //withCredentials([usernamePassword(credentialsId: credentials,
    //                usernameVariable: 'USERNAME', passwordVariable: 'PASSWORD')]) {
    withCredentials([[$class: 'UsernamePasswordMultiBinding', credentialsId: credentials.toString(), passwordVariable: 'PASSWORD', usernameVariable: 'USERNAME']]) {
        println env.USERNAME
        println env.PASSWORD
        sh 'echo $USERNAME and $PASSWORD'
        def authString = "${env.USERNAME}:${env.PASSWORD}".encodeBase64().toString();
        URLConnection conn = new URL("https://api.${githubUrl}.com/repos/${repository}/releases/latest").openConnection();
        conn.setRequestProperty("Authorization", "Basic ${authString}")
        def releases = new groovy.json.JsonSlurper().parse(new BufferedReader(new InputStreamReader(conn.getInputStream())));
        releases.each {
            println it.name
        }
    }
}