Log Message:
ruby-nokogiri: update to 1.8.2.

Upstream changelog (from CHANGELOG.md):

# 1.8.2 / 2018-01-29

## Security Notes

[MRI] The update of vendored libxml2 from 2.9.5 to 2.9.7 addresses at least one \ 
published vulnerability, CVE-2017-15412. [#1714 has complete details]

## Dependencies

* [MRI] libxml2 is updated from 2.9.5 to 2.9.7
* [MRI] libxslt is updated from 1.1.30 to 1.1.32

## Features

* [MRI] OpenBSD installation should be a bit easier now. [#1685] (Thanks, \ 
@jeremyevans!)
* [MRI] Cross-built Windows gems now support Ruby 2.5

## Bug fixes

* Node#serialize once again returns UTF-8-encoded strings. [#1659]
* [JRuby] made SAX parsing of characters consistent with C implementation \ 
[#1676] (Thanks, @andrew-aladev!)
* [MRI] Predefined entities, when inspected, no longer cause a segfault. [#1238]