Gem updates (#2161)
Gem updates (#2161)

* Update rubocop from 0.24 to 0.52

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-8418

* Update yard from 0.8 to 0.9.11

https://nvd.nist.gov/vuln/detail/CVE-2017-17042

middleman/middleman,middleman/middleman,middleman/middleman,middleman/middleman