make install compatibility with sudo and root not having cargo

[RobertMueller2]

• My cargo is installed to $HOME/.local/bin via rustup, root doesn't have it.
• if I want to install satty to /usr/local, I need root to do that.
• install depends on build-release, so make install includes cargo build --release, which root can't do.

Of course, I can use make build-release; touch build-release; sudo make install; rm build-release as a workaround. Or install cargo for root, of course. But it'd be nice if I didn't have to. ;)

I think the easiest is to have install depend on the actual file target/release/satty instead of build-release.

[gabm]

thanks for your report. I agree that this is suboptimal.

I am not very experienced with makefiles, could you create a pr?

[RobertMueller2]

Of course, happy to do so. Might take a few days before I find some spare time. :)

[gabm]

fixed in #16