Faster git-clone due to depth=1 (not for developers)

[denji]

• Immediately pulling all sub-modules

[swisspol]

I don't see why this would be necessary: GitUp is actually a very small repo, so cloning time is not an issue.

Besides, telling people to do a shallow clone without explaining what is happening is setting them up for failure. They will end up with half a repo and most Git users have no clue what a shallow clone is (and therefore how to use them).