My bot @gracyimp@botsin.space gave me the same image twice this morning,
within a few seconds, so I asked myself how to improve the randomness.
Indeed, this allowed my bot to publish some images that never were
published!

Fetches a random image from unsplash and toot it with author's attribution

This commit is dedicated to Le Libre au quotidion, who is supporting me with Ğ1.
Many thanks ☺️

1. replace tabs by spaces
2. align assignations
3. no trailing spaces/tabs
4. put a re.compile outside a function, to make it compiled one time
   only