chore(docs): add -u flag to pacman update cmd

[etorres07]

Description

Hello! 👋

According to the Arch wiki, the command sudo pacman -Sy is explicitly discouraged without the -u flag, for upgrading the system:

• "never run pacman -Sy; instead, always use pacman -Syu" from the Arch wiki, System maintenance > Upgrading the system > Avoid certain pacman commands

Partial upgrades (e.g. pacman -Sy) are not supported by Arch and could lead to broken packages (source: https://wiki.archlinux.org/index.php/System_maintenance#Partial_upgrades_are_unsupported).

Also in the Arch and Manjaro wikis, the instructions on how to uprade the system include the -u flag:

• Arch: Pacman > Upgrading packages
• Manjaro: Pacman Overview > Installing Updates

Documentation

• Gatsby tutorial > part zero > pacman distros: https://www.gatsbyjs.com/tutorial/part-zero/#arch-manjaro-and-other-pacman-based-distros
• Tag @gatsbybot/documentation

Related Issues

There is no issue on this matter, but if necessary, I'd be happy to open one if the PR is too soon.

Hope this helps!

[LekoArts]

Thanks! 🙏