Auto merge of #26302 - servo:dependabot/cargo/crossbeam-channel-0.4.2, r=jdm

Bump crossbeam-channel from 0.4.0 to 0.4.2

Bumps [crossbeam-channel](https://github.com/crossbeam-rs/crossbeam) from 0.4.0 to 0.4.2.
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a href="https://github.com/crossbeam-rs/crossbeam/blob/v0.4.2/CHANGELOG.md">crossbeam-channel's changelog</a>.</em></p>
<blockquote>
<h2>[0.4.2] - 2018-06-12</h2>
<h3>Added</h3>
<ul>
<li>Expose the <code>Pointer</code> trait.</li>
<li>Warn missing docs and missing debug impls.</li>
</ul>
<h2>Changed</h2>
<ul>
<li>Update <code>crossbeam-utils</code> to 0.4.</li>
</ul>
<h2>[0.4.1] - 2018-03-20</h2>
<h3>Added</h3>
<ul>
<li>Add <code>Debug</code> impls for <code>Collector</code>, <code>Handle</code>, and <code>Guard</code>.</li>
<li>Add <code>load_consume</code> to <code>Atomic</code>.</li>
</ul>
<h3>Changed</h3>
<ul>
<li>Rename <code>Collector::handle</code> to <code>Collector::register</code>.</li>
</ul>
<h3>Fixed</h3>
<ul>
<li>Remove the <code>Send</code> implementation for <code>Handle</code> (this was a bug). Only
<code>Collector</code>s can be shared among multiple threads, while <code>Handle</code>s and
<code>Guard</code>s must stay within the thread in which they were created.</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="76f6b7cac1"><code>76f6b7c</code></a> Bump to v0.4.2</li>
<li><a href="185d31dd76"><code>185d31d</code></a> Update crossbeam-utils</li>
<li><a href="c8428c8654"><code>c8428c8</code></a> Remove the Garbage struct (closes <a href="https://github-redirect.dependabot.com/crossbeam-rs/crossbeam/issues/12">#12</a>) (<a href="https://github-redirect.dependabot.com/crossbeam-rs/crossbeam/issues/77">#77</a>)</li>
<li><a href="389f77a05a"><code>389f77a</code></a> Rename strict_gc into sanitize (<a href="https://github-redirect.dependabot.com/crossbeam-rs/crossbeam/issues/78">#78</a>)</li>
<li><a href="eed82cc8c3"><code>eed82cc</code></a> Rename Pointer::from/into_data into Pointer::from/into_usize</li>
<li><a href="5259806e2b"><code>5259806</code></a> Warn missing docs and missing debug impls</li>
<li><a href="4061bae609"><code>4061bae</code></a> Expose the Pointer trait as public</li>
<li><a href="3179e799f3"><code>3179e79</code></a> Bump version to 0.4.1</li>
<li><a href="1945247833"><code>1945247</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/crossbeam-rs/crossbeam/issues/72">#72</a> from Amanieu/load_consume</li>
<li><a href="e7a5dae646"><code>e7a5dae</code></a> Fix non-compiling tests</li>
<li>Additional commits viewable in <a href="https://github.com/crossbeam-rs/crossbeam/compare/crossbeam-channel-0.4.0...v0.4.2">compare view</a></li>
</ul>
</details>
<br />

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Cargo.lock

@@ -944,11 +944,12 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-channel"
-version = "0.4.0"
+version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "acec9a3b0b3559f15aee4f90746c4e5e293b701c0f7d3925d24e01645267b68c"
+checksum = "cced8691919c02aac3cb0a1bc2e9b73d89e832bf9a06fc579d4e71b68a2da061"
 dependencies = [
  "crossbeam-utils",
+ "maybe-uninit",
 ]
 
 [[package]]