message: Update license warning message
diff: @@ -86,7 +86,8 @@ export function generatePackageJson(
  if (bowerJson.license.includes('polymer.github.io/LICENSE')) {
  packageJson.license = 'BSD-3-Clause';
  } else if (!spdxLicenseList.has(bowerJson.license)) {
  - console.warn(`"${bowerJson.license}" is not a valid SPDX license`);
  + console.warn(`"${bowerJson.license}" is not a valid SPDX license. ` +
  + `You can find a list of valid licenses at https://spdx.org/licenses/`);
  }
  for (const bowerPackageName in bowerJson.dependencies) {
  