Caching never expires #3
Description
Unless I'm mistaken with how beet caches work, there is an issue with caching involving changing of the source files since the datapack name is the only thing that determines the cache key string. This means if the source files are changed, Observer will not re-compute the differences between the packs since there's a cache pack with the matching key string. Adding the project version to the cache key string may resolve this issue.