Ending long term support for Java 8

[AngledLuffa]

Continuing to support Java 8 is starting to cause multiple issues for maintaining our library, including but not limited to:

• Lucene security fixes are not available to us, as they have discontinued Java 8 support
• Apple GUI interfaces such as for Tregex are nigh impossible to provide, as the latest versions of those dev tools support 9 onwards
• Jollyday updates (including support for the most recent versions of Java) are not possible, as the original Jollyday supports 8-14 and newer versions do not support 8 at all

Accordingly, some time this year we intend to release one last version which supports 8, including the limitations from above, and then transition to Java 11.

Intended upgrades between now and then:

• rebuild the caseless models
• add Semgrex & Ssurgeon support for UD treebanks with enhanced dependencies
• release each of the sub-components such as NER, parser, etc one last time

Intended completion date is summer 2024.

Feedback and opinions are welcome!