feat(cli): Reimplement updateflag

[javorszky]

In #188 golangci-lint was introduced. One of the first rules is unused, which flagged up three unused pieces of data in the codebase. One of them was the flag used for updating, and commented out parts of the code that would handle that.

That code was removed in PR #189 , more specifically commit 69f56a6

This issue is to track adding that back when the time is right.