docs: update Arch installation instructions (#1971)

Author: JonathanRayner

website/docs/installation.mdx

@@ -82,23 +82,13 @@ scoop install task
 This installation method is community owned. After a new release of Task, it may
 take some time until it's available on Scoop.
 
-### AUR
+### Arch
 
-If you're on Arch Linux you can install Task from
-[AUR](https://aur.archlinux.org/packages/go-task-bin) using your favorite
-package manager such as `yay`, `pacaur` or `yaourt`:
+If you're on Arch Linux you can install Task from the official
+[Arch](https://archlinux.org/packages/extra/x86_64/go-task/) repository using `pacman`:
 
 ```shell
-yay -S go-task-bin
-```
-
-Alternatively, there's
-[this package](https://aur.archlinux.org/packages/go-task) which installs from
-the source code instead of downloading the binary from the
-[releases page](https://github.com/go-task/task/releases):
-
-```shell
-yay -S go-task
+pacman -S go-task
 ```
 
 This installation method is community owned.