v1.2.0 - Gatsby fixes & improved downloading

Migrate dependencies, especially GatsbyJS which got plenty of networking issues fixed.

v1.1.0 - gatsby-source-filesystem support

• add support for gatsby-source-filesystem
• rewrites code and caching to be more efficient
• this plugin now has unit tests

v1.0.0

Breaking: Adds compatibility with Gatsby v4. Will probably create issues with Gatsby v2 now.