Update documentation with option to install helm on Windows via scoop (#5207)

Signed-off-by: Marcin Kłopotek <marcin.klopotek@gmail.com>

docs/install.md

@@ -45,7 +45,7 @@ brew install kubernetes-helm
 (Note: There is also a formula for emacs-helm, which is a different
 project.)
 
-### From Chocolatey (Windows)
+### From Chocolatey or scoop (Windows)
 
 Members of the Kubernetes community have contributed a [Helm package](https://chocolatey.org/packages/kubernetes-helm) build to
 [Chocolatey](https://chocolatey.org/). This package is generally up to date.
@@ -54,6 +54,12 @@ Members of the Kubernetes community have contributed a [Helm package](https://ch
 choco install kubernetes-helm
 ```
 
+The binary can also be installed via [`scoop`](https://scoop.sh) command-line installer.
+
+```
+scoop install helm
+```
+
 ## From Script
 
 Helm now has an installer script that will automatically grab the latest version