Compile API 9 in Java 8

[amnoah]

Major SpongeAPI version

9.0.0

Is this likely to be a breaking change?

No

What are you requesting?

Hi there, I've been redirected to report this issue here from the Discord server.

I recently attempted to include Sponge compatibility within a plugin of mine, but I found that the API 9 dependency available on the Maven repository has been compiled with Java 17.

Compile log: https://pastebin.com/G9fBENBn My pom.xml for the module: https://pastebin.com/CF8MXuGF

Unless things have changed, in which case you should update the text stating that Java 8 is required for the API and Java 16 is recommended for development in the ReadMe, then this doesn't seem right.