message: chore: add JOSS badge to README
diff: @@ -135,6 +135,16 @@ by Nextstrain team
  </p>
  +<p align="center">
  +
  + <a href="https://joss.theoj.org/papers/b0e8e7f231ddfc61616de6b56f32b79f">
  + <img
  + src="https://joss.theoj.org/papers/b0e8e7f231ddfc61616de6b56f32b79f/status.svg">
  + alt="JOSS submission status"
  + </a>
  +
  +</p>
  +
  ---
  <p align="center">
  