Add findutils to required packages.

1 job for patch-1 in 5 minutes and 49 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Test
failed #26600
build

00:05:49

 
Name Stage Failure
failed
build Test
   │                         ^^^^^^^^^^^^^^^^ Did you forget to define a URL for `from Wikimedia`?

= hint: declare the link's URL. For example: `[from Wikimedia]: http://example.com/`

Error: ErrorMessage { msg: "One or more incorrect links" }
2020-05-04 01:53:36 [ERROR] (mdbook::renderer): Renderer exited with non-zero return code.
2020-05-04 01:53:36 [ERROR] (mdbook::utils): Error: Rendering failed
2020-05-04 01:53:36 [ERROR] (mdbook::utils): Caused By: The "linkcheck" renderer failed
ERROR: Job failed: exit code 1