NestableJarGenerationTask.Metadata record should be public for configuration cache support

[lukebemish]

This record https://github.com/FabricMC/fabric-loom/blob/dev/1.7/src/main/java/net/fabricmc/loom/build/nesting/NestableJarGenerationTask.java#L237 is currently protected. As it is used as an (albeit protected) task input type, gradle will attempt to construct a new one during restoration from configuration cache; it will fail to do so as the record is protected, and it does not create any sort of bouncer to its constructor in its generated task subclass. See https://gist.github.com/Nyfaria/1212eae73685830aeab58bce50cca4d1

[modmuss50]

Thanks, as far as im aware the whole remap jar task + related stuff such as this is all thats left to deal with. Thankfully this seems quite easy to resolve.