+ added tested support for 1.20.4, 1.20.6 and 1.21

~ updated to Java 21
~ updated some internal code (but still stick to the old coding style, lol)
~ updated bStats metrics

- dropped support for 1.9, 1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17 including indirect support of 1.18 and 1.19
- removed unnecessary aliases

If you want to use it on a server, older than 1.20, then please use the previous release 1.17_R2. This is an old version, but it still works with a variety of servers.

Thank you for using my plugins!