Add scoop install for windows (#48)

Adding scoop install to setup for windows for ffmpeg

README.md

@@ -32,6 +32,9 @@ brew install ffmpeg
 
 # on Windows using Chocolatey (https://chocolatey.org/)
 choco install ffmpeg
+
+# on Windows using Scoop (https://scoop.sh/)
+scoop install ffmpeg
 ```