message: Fix file writing
diff: @@ -50,7 +50,7 @@ export class FileConfig<T> implements JsonConfig<T> {
  // these files.
  const tempFilename = `${this.filename}.${Date.now()}`;
  try {
  - fs.writeFileSync(tempFilename, this.dataJson, {encoding: 'utf8'});
  + fs.writeFileSync(tempFilename, JSON.stringify(this.dataJson), {encoding: 'utf8'});
  fs.renameSync(tempFilename, this.filename);
  } catch (error) {
  logging.error(`Error writing config ${this.filename} ${error}`);
  