GitHub API usage removed. The tarball is used from codeload.github.com
Close#361, PR #363
BREAKING CHANGE:
The folder names of packages fetched from GitHub changed to not contain
information that would require an API request to get.
Old folder name: is-negative@github+kevva+is-negative+HEAD
New folder name: github+kevva+is-negative+HEAD
Users are forced to redownload their stores to avoid orphan folders after
the naming change.