docs: add pacstall installation methode

Author: vmaerten

website/docs/installation.mdx

@@ -146,6 +146,15 @@ can install Task from [winget-pkgs](https://github.com/microsoft/winget-pkgs).
 winget install Task.Task
 ```
 
+### Pacstall
+If you are using Debian or Ubuntu, and have [Pacstall](https://pacstall.dev/) installed, you can install Task by running:
+
+```shell
+pacstall -I go-task-deb
+```
+
+This installation method is community owned. After a new release of Task, it may take some time until it's available in [Pacstall](https://pacstall.dev/packages/go-task-deb).
+
 ## Get The Binary
 
 ### Binary