deps: Update go-org to v1.3.0

deps: Update go-org to v1.3.0

- Add support for image links (i.e. link with image as description)
- Kinda breaking: Wrap headlines and headline+content in containers as emacs
  Org mode does. Could break people's styles - I don't expect it, but who knows
  what counts as sane when it comes to css.

  Before:

  ```
  <h2 id="headline-1">FOO</h2>
  foo bar
  ```

  After:

  ```
  <div id="outline-container-headline-1" class="outline-2">
  <h2 id="headline-1">FOO</h2>
  <div id="outline-text-headline-1" class="outline-text-2">
  foo bar
  </div>
  </div>
  ```