Unity build post process script to automatically bump iOS and Android version numbers

BuildNumberIncrementer.cs

#if UNITY_EDITOR
using UnityEditor;
using UnityEditor.Callbacks;
using UnityEngine;

public class BuildNumberIncrementer
{
  [PostProcessBuild]
  public static void OnBuildComplete(BuildTarget buildTarget, string pathToBuiltProject)
  {
    IncrementBuildNumber(buildTarget);
  }

  private static void IncrementBuildNumber(BuildTarget buildTarget)
  {
    switch (buildTarget)
    {
      case BuildTarget.iOS:
        BumpiOSBuildNumber();
        break;
      case BuildTarget.Android:
        BumpAndroidBuildNumber();
        break;
      default:
        break;
    }
  }

  private static void BumpiOSBuildNumber()
  {
    var buildNumberString = PlayerSettings.iOS.buildNumber;
    int buildNumber;
    if (int.TryParse(buildNumberString, out buildNumber))
    {
      PlayerSettings.iOS.buildNumber = (buildNumber + 1).ToString();
      Debug.Log("Bumped iOS Build Number to " + PlayerSettings.iOS.buildNumber);
      AssetDatabase.SaveAssets();
    }
  }

  private static void BumpAndroidBuildNumber()
  {
    var buildNumber = PlayerSettings.Android.bundleVersionCode;
    PlayerSettings.Android.bundleVersionCode = buildNumber + 1;
    Debug.Log("Bumped Android Bundle Version Code to " + PlayerSettings.Android.bundleVersionCode);
    AssetDatabase.SaveAssets();
  }
}
#endif