install: recognize more windows os formats (#336)

Author: devmatteini

install.sh

@@ -59,7 +59,7 @@ get_os(){
   local os
   os=$(uname -s)
   case "$os" in
-    MINGW* | Win*) echo "Windows" ;;
+    MINGW* | Win* | MSYS* | CYGWIN*) echo "Windows" ;;
     Darwin*) echo "Darwin" ;;
     Linux*) echo "Linux" ;;
     *) error "Unsupported operating system: $os" ;;