public Builder setComment(String comment) {
      this.comment = comment;
      return this;
    }
Represents an item in the container configuration's {@code history} list.

@see <a href=https://github.com/opencontainers/image-spec/blob/master/config.md#properties>OCI
    image spec ({@code history} field)</a>
jib-core/src/main/java/com/google/cloud/tools/jib/image/json/HistoryEntry.java