Log Message:
ruby-memoist: update to 0.16.2.

Upstream changes (from CHANGELOG.md):

v0.16.2 (2019-12-04)

Merged pull requests:

* Fix regression introduced by frozen symbol fix #86 (sebjacobs)

v0.16.1 (2019-11-08)

Merged pull requests:

* Remove ruby 1.9.2 from travis build matrix #84 (unasuke)
* Make Memoist.escape_punctuation compatible with MRI 2.7 #82 (casperisfine)
* add 2.5.1 to travis #77 (matthewrudy)
* Remove ghit.me #74 (matthewrudy)
* Place sample code for execution in README.md #73 (3nan3)
* Require Ruby >=1.9.2 #69 (matthewrudy)