We use it during installation and add it to PATH, but then
don't instruct ghcup to actually use this directory at runtime.
This leads to:
1. ghcup is in /usr/local/.ghcup/bin/
2. `ghcup install cabal latest` will actually install into ~/.ghcup/bin/
3. since ~/.ghcup/bin/ is not in PATH, but /usr/local/.ghcup/bin/ is,
the new binary is not visible to the user
This issues does not exist on darwin, because there we use
~/.ghcup/bin/.
https://downloads.haskell.org/ghcup/tmp/aarch64-linux-ghcup-0.1.18.1
b38865e056