- Skip modStaticResource in the content extraction to prevent issues with binary file content

Inspired by https://github.com/ahaller/Gitify/commit/50d3f667b8ac822ec95967dcf9b98c56b78429db
- Add ability to read composite primary keys, when `primary` is set to an array in the `.gitify` data object. (thanks @ahaller)
Add note to readme about versioning/changelog