Could not find method leftShift() for arguments after updating studio 3.4

To solve this error, change << with doLast like this.

task incrementBetaVersion  {
    doLast {
        println("Incrementing Beta Version Number...")
        incrementVersionNumber('BetaVersionNumber')
        println("Incrementing Beta Version Number...")
        incrementVersionName('BetaVersionName')
    }
}

Left shift operator represent’s doLast { }.

<< was deprecated in Gradle 4.x and removed in Gradle 5.0

From Docs:

<< for task definitions no longer works. In other words, you can not use the syntax

task myTask << { …​ }.

Use the Task.doLast() method instead, like this:

task myTask {
    doLast {
        ...
        ...
    }
}

More info here:
https://discuss.gradle.org/t/could-not-find-method-leftshift-for-arguments-on-task-of-type-org-gradle-api-defaulttask/30614

https://docs.gradle.org/current/userguide/upgrading_version_4.html#changes_5.0