[Security] Bump nokogiri from 1.8.2 to 1.8.4

[dependabot-preview]

Bumps nokogiri from 1.8.2 to 1.8.4. This update includes security fixes.

Vulnerabilities fixed

Sourced from The Ruby Advisory Database.

Revert libxml2 behavior in Nokogiri gem that could cause XSS
[MRI] Behavior in libxml2 has been reverted which caused
CVE-2018-8048 (loofah gem), CVE-2018-3740 (sanitize gem), and
CVE-2018-3741 (rails-html-sanitizer gem). The commit in question is
here:

GNOME/libxml2@960f0e2

and more information is available about this commit and its impact
here:

https://github-redirect.dependabot.com/flavorjones/loofah/issues/144

This release simply reverts the libxml2 commit in question to protect
users of Nokogiri's vendored libraries from similar vulnerabilities.

If you're offended by what happened here, I'd kindly ask that you
comment on the upstream bug report here:

https://bugzilla.gnome.org/show_bug.cgi?id=769760

Patched versions: >= 1.8.3
Unaffected versions: none

Changelog

Sourced from nokogiri's changelog.

1.8.4 / 2018-07-03

Bug fixes

• [MRI] Fix memory leak when creating nodes with namespaces. (Introduced in v1.5.7) [Update graphql to version 1.6.6 #1771]

1.8.3 / 2018-06-16

Security Notes

[MRI] Behavior in libxml2 has been reverted which caused CVE-2018-8048 (loofah gem), CVE-2018-3740 (sanitize gem), and CVE-2018-3741 (rails-html-sanitizer gem). The commit in question is here:

GNOME/libxml2@960f0e2

and more information is available about this commit and its impact here:

https://github-redirect.dependabot.com/flavorjones/loofah/issues/144

This release simply reverts the libxml2 commit in question to protect users of Nokogiri's vendored libraries from similar vulnerabilities.

If you're offended by what happened here, I'd kindly ask that you comment on the upstream bug report here:

https://bugzilla.gnome.org/show_bug.cgi?id=769760

Dependencies

• [MRI] libxml2 is updated from 2.9.7 to 2.9.8

Features

• Node#classes, #add_class, #append_class, and #remove_class are added.
• NodeSet#append_class is added.
• NodeSet#remove_attribute is a new alias for NodeSet#remove_attr.
• NodeSet#each now returns an Enumerator when no block is passed (Thanks, park53kr!)
• [JRuby] General improvements in JRuby implementation (Thanks, kares!)

Bug fixes

• CSS attribute selectors now gracefully handle queries using integers. [Mejoras en la velocidad de las búsquedas #711]
• Handle ASCII-8BIT encoding on fragment input [Updates admin and moderation texts #553]
• Handle non-string return values within Reader [Proposals summary #898]
• [JRuby] Allow Node#replace to insert Comment and CDATA nodes. [Users without email #1666]
• [JRuby] Stability and speed improvements to Node, Sax::PushParser, and the JRuby implementation [Help texts on forms #1708, #1710, #1501]

Commits

• 254f341 version bump to v1.8.4
• 056f66d enforcing formatting in xml_node.c
• ca4f9b2 Merge branch '1771-memory-leak'
• 0d26561 fix memory leak with creating nodes with a namespace
• 117ca2e README format
• 20e11c3 version bump to 1.8.3
• be8a240 update CHANGELOG
• 06ac6ba Merge branch '1765-enumerator'
• 00bafb7 add test coverage for NodeSet#each enum
• 75517e0 '#each' returns enumerator when no block given
• Additional commits viewable in compare view

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

---

Note: This repo was added to Dependabot recently, so you'll receive a maximum of 5 PRs for your first few update runs. Once an update run creates fewer than 5 PRs we'll remove that limit.

You can always request more updates by clicking Bump now in your Dependabot dashboard.

Dependabot commands and options

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot merge will merge this PR after your CI passes on it
• @dependabot cancel merge will cancel a previously requested merge
• @dependabot reopen will reopen this PR if it is closed
• @dependabot ignore this [patch|minor|major] version will close this PR and stop Dependabot creating any more for this minor/major version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this dependency will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)
• @dependabot use these labels will set the current labels as the default for future PRs for this repo and language
• @dependabot use these reviewers will set the current reviewers as the default for future PRs for this repo and language
• @dependabot use these assignees will set the current assignees as the default for future PRs for this repo and language
• @dependabot use this milestone will set the current milestone as the default for future PRs for this repo and language
• @dependabot badge me will comment on this PR with code to add a "Dependabot enabled" badge to your readme

Additionally, you can set the following in your Dependabot dashboard:

• Update frequency (including time of day and day of week)
• Automerge options (never/patch/minor, and dev/runtime dependencies)
• Pull request limits (per update run and/or open at any time)
• Out-of-range updates (receive only lockfile updates, if desired)
• Security updates (receive only security updates, if desired)

Finally, you can contact us by mentioning @dependabot.