[consideration] Read MC version/java version from the versions json

[electronicboy]

https://github.com/PaperMC/Paperclip/commit/9878daa51d6da3fff26d8f09a5703d19b7ead6f0

Not sure if this is really worth the 10 minutes it requires, but maybe worth doing so given that the info is there and saves us potential headaches, etc