Document Scoop and AUR install paths in README

Scoop bucket has been seeded for v0.1.4 and the AUR qn-bin package is
registered + installable via yay. Two new install snippets so users on
Windows + Arch don't have to know about the GitHub Releases page.
Homebrew was already in the install matrix.

Author: johnpmitsch

README.md

@@ -43,6 +43,19 @@ The crate name is `quicknode-cli` but the installed binary is `qn`.
 brew install quicknode/tap/qn
 ```
 
+### Scoop (Windows)
+
+```powershell
+scoop bucket add quicknode https://github.com/quicknode/scoop-bucket
+scoop install quicknode/qn
+```
+
+### Arch Linux (AUR)
+
+```sh
+yay -S qn-bin   # or any other AUR helper
+```
+
 ### From source
 
 ```sh