Incorrect attachment names in JATS

## `06802` Attachments have content hash names, but JATS refers to them with relative paths that don't exist like `../assets/figure/etc.png` - https://github.com/openjournals/joss-papers/blob/acc35385646bf0a64e8b2ba3c87f745f93dc9a13/joss.06802/paper.jats/10.21105.joss.06802.jats#L159 - https://github.com/openjournals/joss-papers/blob/acc35385646bf0a64e8b2ba3c87f745f93dc9a13/joss.06802/paper.jats/10.21105.joss.06802.jats#L185 - https://github.com/openjournals/joss-papers/blob/acc35385646bf0a64e8b2ba3c87f745f93dc9a13/joss.06802/paper.jats/10.21105.joss.06802.jats#L285 - https://github.com/openjournals/joss-papers/blob/acc35385646bf0a64e8b2ba3c87f745f93dc9a13/joss.06802/paper.jats/10.21105.joss.06802.jats#L232