docs: Deprecation note

Author: osipxd

README.md

@@ -1,7 +1,14 @@
-BukkitGradle [![Version](https://img.shields.io/github/release/EndlessCodeGroup/BukkitGradle/all.svg?style=flat-square)](https://plugins.gradle.org/plugin/ru.endlesscode.bukkitgradle) [![Build Status](https://img.shields.io/travis/EndlessCodeGroup/BukkitGradle.svg?style=flat-square)](https://travis-ci.org/EndlessCodeGroup/BukkitGradle) [![license](https://img.shields.io/github/license/EndlessCodeGroup/BukkitGradle.svg?style=flat-square)](https://github.com/EndlessCodeGroup/BukkitGradle/blob/master/LICENSE)
+BukkitGradle
+[![Version](https://img.shields.io/github/release/EndlessCodeGroup/BukkitGradle/all.svg?style=flat-square)](https://plugins.gradle.org/plugin/ru.endlesscode.bukkitgradle)
+[![Build Status](https://img.shields.io/travis/EndlessCodeGroup/BukkitGradle.svg?style=flat-square)](https://travis-ci.org/EndlessCodeGroup/BukkitGradle)
+[![license](https://img.shields.io/github/license/EndlessCodeGroup/BukkitGradle.svg?style=flat-square)](https://github.com/EndlessCodeGroup/BukkitGradle/blob/master/LICENSE)
 ============
 Gradle utilities for easier writing Bukkit plugins.
 
+> [!WARNING]
+> This plugin is not being maintained anymore,
+> consider switching to [spigradle](https://github.com/spigradle/spigradle).
+
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