Fix message about repository doesn't support architecture 'i386'

I recently started using the Brave browser and after adding their repository to my system I got this message when running apt update:

N: Skipping acquire of configured file 'main/binary-i386/Packages' as repository 'https://brave-browser-apt-release.s3.brave.com stable InRelease' doesn't support architecture 'i386'

The N is telling me it's simply a notice but I adhere to the philosophy of keeping things as clean as possible so I still want to fix it.

Unnecessary clutter can sometimes hide or obscure real problems.

The solution is simply to tell the system what architecture this repository is for. Simply opening the repository file /etc/apt/sources.list.d/brave-browser-release.list and define arch=amd64 would do the trick:

deb [arch=amd64 signed-by=/usr/share/keyrings/brave-browser-archive-keyring.gpg] https://brave-browser-apt-release.s3.brave.com/ stable main