public String getJsonString() throws IOException {
    try (OutputStream outputStream = new ByteArrayOutputStream()) {
      new ObjectMapper().writeValue(outputStream, skaffoldFilesTemplate);
      return outputStream.toString();
    }
  }
Gets the added files in JSON format.

@return the files in a JSON string
@throws IOException if writing out the JSON fails
jib-plugins-common/src/main/java/com/google/cloud/tools/jib/plugins/common/SkaffoldFilesOutput.java