Unity Gradle Android plugin version setter

GradleAndroidPluginVersionSetter.cs

#if UNITY_ANDROID
using System.IO;
using System.Text.RegularExpressions;
using UnityEditor.Android;

public class GradleAndroidPluginVersionSetter : IPostGenerateGradleAndroidProject
{
    public const string GradleAndroidPluginVersion = "3.4.3";

    public int callbackOrder => 0;

    public void OnPostGenerateGradleAndroidProject(string path)
    {
#if UNITY_2019_1_OR_NEWER
        // Use project's root folder instead of /unityLibrary
        path = Path.GetDirectoryName(path);
#endif

        SetupGradleAndroidPlugin(path, GradleAndroidPluginVersion);
    }

    public static void SetupGradleAndroidPlugin(string path, string androidPluginVersion)
    {
        string buildScript = File.ReadAllText(Path.Combine(path, "build.gradle"));
        buildScript = Regex.Replace(buildScript, @"(?<=classpath\s'com.android.tools.build:gradle:)[^']+", androidPluginVersion);
        File.WriteAllText(Path.Combine(path, "build.gradle"), buildScript);
    }
}
#endif