RUSTSEC-2020-0095: difference is unmaintained

[github-actions]

difference is unmaintained

Details
Status	unmaintained
Package	difference
Version	2.0.0
URL	johannhof/difference.rs#45
Date	2020-12-20

The author of the difference crate is unresponsive.

Maintained alternatives:

• pretty_assertions

• dissimilar

• treediff

• diffus

See advisory page for additional details.