Update homebrew path for Apple Silicon

[numbertheory]

When using ./screenfetch-dev on my Apple Silicon Mac (Mac mini (M1, 2020)), there was a line of output that errors out with the following text.

ls: /usr/local/Cellar/: No such file or directory

The reason is because Homebrew, on the M1 platform, installs to /opt/homebrew/Cellar, rather than the /usr/local/Cellar.

https://apple.stackexchange.com/questions/410825/apple-silicon-port-all-homebrew-packages-under-usr-local-opt-to-opt-homebrew

This patch should resolve that. Thanks!