devel/rubygem-licensee: Update from 8.2.0 to 8.7.0

Changes of 8.7.0 including:

• New: Expose license rules as Licensee::Rule (#148)
• New: Recognize underlined license headers in READMEs (#138, props @pchaigno)
• Fixed: Running licensee against a single file on Windows (#144, props @sschuberth)

There were many more changes, but there is no changelog. You need to consult
https://github.com/benbalter/licensee/releases for a list of all changes.