This means that this methode has been deprecated see the documentation https://static.javadoc.io/io.appium/java-client/6.1.0/io/appium/java_client/android/AndroidKeyCode.html
as stated by the documentation use AndroidKey instead
https://static.javadoc.io/io.appium/java-client/6.1.0/io/appium/java_client/android/nativekey/AndroidKey.html