Unity post build minor version increment

using System;
using UnityEngine;
using UnityEditor;
using UnityEditor.Callbacks;

/// <summary>
/// Automatically increment InternalSettingsInstance.versionBuild after an EXE is built.
/// </summary>
public class BuildPostprocessor {
    [PostProcessBuildAttribute (1)]
    public static void OnPostprocessBuild (BuildTarget target, string pathToBuiltProject) {

        // to update major or minor version, manually set it in Edit>Project Settings>Player>Other Settings>Version

        // this will also set Application.version which is readonly
        string [] versionParts = PlayerSettings.bundleVersion.Split ('.');
        if (versionParts.Length != 3 /*|| versionParts [2].ParseInt (-1) == -1*/) { //idk what this did, but it broke
            Debug.LogError ("BuildPostprocessor failed to update version " + PlayerSettings.bundleVersion);
            return;
        }
        // major-minor-build
        versionParts [2] = (Int32.Parse( versionParts [2]) + 1).ToString ();
        PlayerSettings.bundleVersion = string.Join (".", versionParts);
    }
}