Use git to get the package files

[niklas-heer]

Downloading the files is potentially prone to errors, because there is no integrity check for the download of these files.
You could just partially clone the repo and this would fix that issue.

But you would need deploy keys and an install mechanism for them to work.

See:

• https://unix.stackexchange.com/a/241327 (for Github - via svn)
• https://stackoverflow.com/a/163769 (for Gitlab)