I have found Micropublish that suggests it could be used to edit posts given its URL but when I tried to use it to edit the prior post it generated an internal server error. An Implementation Status table on the Indieweb Micropub clients page suggests the “problem” is that micro.blog does not support/expose the delete, undelete, or update actions; the only action it appears you can do from a Micropub client is create.
I notice that OmniBear hasn’t been updated in more than a year so I might start using Micropublish more, it is even possible to self host the app.