1.17 support

[Pjiwm]

IMPORTANT: Please do not create a Pull Request without creating an issue first.

Any change needs to be discussed before proceeding. Failure to do so may result in the rejection of the pull request.

Please provide enough information so that others can review your pull request:

Server currently runs on some versions of 1.16.x, Minecraft 1.17 is out and support for this version is needed.

Explain the details for making this change. What existing problem does the pull request solve?

Currently using this plugin on a 1.17 server will not work.
The current things are needed:

• Plugin runs on 1.17.1
• Plugin runs on 1.17
• Plugin runs on 1.16.5
• Plugin runs on 1.16.4
• Plugin runs on 1.16.3
• Plugin runs on 1.16.2
• Plugin runs on 1.16.1
• Plugin runs on 1.16

Test plan (required):
Demonstrate the code is solid. Example: The exact commands you ran and their output, screenshots / videos if the pull request has visual changes.

1. swap spigot.jar file of test server with needed version
2. run server
3. ececute plugins command and check if plugin is still green
4. if on 1.17.x go on server to check if mob behavior is the same as on 1.16.x
   Closing issues
   [FEATURE]: 1.17 support #21

Put closes #XXXX in your comment to auto-close the issue that your PR fixes (if such).