feat: add downloadUrl (#1449)

prepare_vscode.sh

@@ -103,6 +103,7 @@ setpath "product" "twitterUrl" "https://go.microsoft.com/fwlink/?LinkID=533687"
 
 if [[ "${DISABLE_UPDATE}" != "yes" ]]; then
   setpath "product" "updateUrl" "https://vscodium.now.sh"
+  setpath "product" "downloadUrl" "https://github.com/VSCodium/vscodium/releases"
 fi
 
 if [[ "${VSCODE_QUALITY}" == "insider" ]]; then