Bump slotmap from 1.0.6 to 1.0.7 (paritytech#5096)

Bumps [slotmap](https://github.com/orlp/slotmap) from 1.0.6 to 1.0.7.
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a
href="https://github.com/orlp/slotmap/blob/master/RELEASES.md">slotmap's
changelog</a>.</em></p>
<blockquote>
<h1>Version 1.0.7</h1>
<ul>
<li>Added <code>clone_from</code> implementations for all slot
maps.</li>
<li>Added <code>try_insert_with_key</code> methods that accept a
fallible closure.</li>
<li>Improved performance of insertion and key hashing.</li>
<li>Made <code>new_key_type</code> resistant to shadowing.</li>
<li>Made iterators clonable regardless of item type clonability.</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/orlp/slotmap/commit/c905b6ced490551476cb7c37778eb8128bdea7ba"><code>c905b6c</code></a>
Release 1.0.7.</li>
<li><a
href="https://github.com/orlp/slotmap/commit/cdee6974d5d57fef62f862ffad9ffe668652d26f"><code>cdee697</code></a>
Merge pull request <a
href="https://github.com/orlp/slotmap/issues/107">#107</a> from
waywardmonkeys/minor-doc-tweaks</li>
<li><a
href="https://github.com/orlp/slotmap/commit/4456784a9bce360ec38005c9f4cbf4b4a6f92162"><code>4456784</code></a>
Fix a typo and add some backticks.</li>
<li><a
href="https://github.com/orlp/slotmap/commit/a7287a2caa80bb4a6d7a380a92a49d48535357a5"><code>a7287a2</code></a>
Merge pull request <a
href="https://github.com/orlp/slotmap/issues/99">#99</a> from
chloekek/hash-u64</li>
<li><a
href="https://github.com/orlp/slotmap/commit/eeaf92e5b3627ac5a2035742c6e2818999ac3d0c"><code>eeaf92e</code></a>
Provide explicit impl Hash for KeyData</li>
<li><a
href="https://github.com/orlp/slotmap/commit/ce6e1e02bb2c2074d8d581e87ad9c2f72ce495c3"><code>ce6e1e0</code></a>
Lint invalid_html_tags has been renamed, but not really necessary.</li>
<li><a
href="https://github.com/orlp/slotmap/commit/941c39301211a03385e8d7915d0d31b6f6f5ecd5"><code>941c393</code></a>
Fixed remaining references to global namespace in new_key_type
macro.</li>
<li><a
href="https://github.com/orlp/slotmap/commit/cf7e44c05d777440687cfa0d439a31fdec50cc3a"><code>cf7e44c</code></a>
Added utility module.</li>
<li><a
href="https://github.com/orlp/slotmap/commit/5575afe1a31c634d5ab15d273ad8793f6711f8b1"><code>5575afe</code></a>
Ensure insert always has fast path.</li>
<li><a
href="https://github.com/orlp/slotmap/commit/7220adc6fa9defb356699f3d96af736e9ef477b5"><code>7220adc</code></a>
Cargo fmt and added test case for cloneable iterators.</li>
<li>Additional commits viewable in <a
href="https://github.com/orlp/slotmap/compare/v1.0.6...v1.0.7">compare
view</a></li>
</ul>
</details>
<br />


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