private static ImageReference getGeneratedTargetDockerTag(
      RawConfiguration rawConfiguration,
      ProjectProperties projectProperties,
      HelpfulSuggestions helpfulSuggestions)
      throws InvalidImageReferenceException {
    return ConfigurationPropertyValidator.getGeneratedTargetDockerTag(
        rawConfiguration.getToImage().orElse(null), projectProperties, helpfulSuggestions);
  }
Creates an {@link Instant} based on the config value. The value can be:

<ol>
  <li>{@code EPOCH} to return epoch
  <li>{@code USE_CURRENT_TIMESTAMP} to return the current time
  <li>date in ISO 8601 format
</ol>

@param configuredCreationTime the config value
@param projectProperties used for logging warnings
@return corresponding {@link Instant}
@throws InvalidCreationTimeException if the config value is invalid
jib-plugins-common/src/main/java/com/google/cloud/tools/jib/plugins/common/PluginConfigurationProcessor.java