Use zipfile when installing in Windows

The release for Windows is bundled in a zipfile instead of a tarball.
This change fixes the download URL in Windows to use .zip instead of .tar.gz

install-binary.sh

@@ -61,6 +61,8 @@ initOS() {
   Darwin) OS='darwin' ;;
   Linux) OS='linux' ;;
   esac
+
+  EXT=
 }
 
 # verifySupported checks that the os/arch combination is supported for
@@ -83,10 +85,14 @@ verifySupported() {
 # getDownloadURL checks the latest available version.
 getDownloadURL() {
   version="$(< "$HELM_PLUGIN_DIR/$PLUGIN_MANIFEST" grep "version" | cut -d '"' -f 2)"
+  ext="tar.gz"
+  if [ "$OS" = "windows" ]; then
+    ext="zip"
+  fi
   if [ "$SCRIPT_MODE" = "install" ] && [ -n "$version" ]; then
-    DOWNLOAD_URL="https://github.com/${PROJECT_GH}/releases/download/v${version}/${PROJECT_NAME}_${version}_${OS}_${ARCH}.tar.gz"
+    DOWNLOAD_URL="https://github.com/${PROJECT_GH}/releases/download/v${version}/${PROJECT_NAME}_${version}_${OS}_${ARCH}.${ext}"
   else
-    DOWNLOAD_URL="https://github.com/${PROJECT_GH}/releases/latest/download/${PROJECT_NAME}_${version}_${OS}_${ARCH}.tar.gz"
+    DOWNLOAD_URL="https://github.com/${PROJECT_GH}/releases/latest/download/${PROJECT_NAME}_${version}_${OS}_${ARCH}.${ext}"
   fi
 }