Changes to cask

As per [the recent change to cask](https://github.com/caskroom/homebrew-cask/issues/13201), the applications will not be installed to `/opt/homebrew-cask/Caskroom`.

Seems like you are using the default location while installing the packages [here](https://github.com/klmr/system-setup/blob/f6a92b7e2d530e3843ae3717576c514a956f71e8/setup.sh#L58) which will be `/usr/local/Caskroom/` according to the changes. This will make [this](https://github.com/klmr/system-setup/blob/f6a92b7e2d530e3843ae3717576c514a956f71e8/upgrade.sh#L6) line not work as expected.

Read setup.sh at line 58 and upgrade.sh at line 6, then compare their Caskroom paths with the linked Homebrew Cask change. Verify the setup and upgrade flow uses the current installation location and confirm that upgrading installed applications works as expected.

Written by the indexing model from the issue text.