Bump boto3 from 1.18.59 to 1.18.60 (#64)

Bumps [boto3](/~https://github.com/boto/boto3) from 1.18.59 to 1.18.60.
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a href="/~https://github.com/boto/boto3/blob/develop/CHANGELOG.rst">boto3's changelog</a>.</em></p>
<blockquote>
<h1>1.18.60</h1>
<ul>
<li>api-change:<code>cloudsearch</code>: [<code>botocore</code>] Adds an additional validation exception for Amazon CloudSearch configuration APIs for better error handling.</li>
<li>api-change:<code>ecs</code>: [<code>botocore</code>] Documentation only update to address tickets.</li>
<li>api-change:<code>mediatailor</code>: [<code>botocore</code>] MediaTailor now supports ad prefetching.</li>
<li>api-change:<code>ec2</code>: [<code>botocore</code>] EncryptionSupport for InstanceStorageInfo added to DescribeInstanceTypes API</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="/~https://github.com/boto/boto3/commit/ef35d5d4a8d6b16436e681bc223212f683a7b182"><code>ef35d5d</code></a> Merge branch 'release-1.18.60'</li>
<li><a href="/~https://github.com/boto/boto3/commit/573483715e309d2176a9999ee2d616631b41a136"><code>5734837</code></a> Bumping version to 1.18.60</li>
<li><a href="/~https://github.com/boto/boto3/commit/e766ff178fcefc1441bf123594482462b26182ac"><code>e766ff1</code></a> Add changelog entries from botocore</li>
<li><a href="/~https://github.com/boto/boto3/commit/62ceb0543d0346a03df2f057e20287f5427ca429"><code>62ceb05</code></a> Move from 3.10-dev to 3.10 (<a href="https://github-redirect.dependabot.com/boto/boto3/issues/3036">#3036</a>)</li>
<li><a href="/~https://github.com/boto/boto3/commit/4f667ba861f708d7f225ae075036ab0d3b8282db"><code>4f667ba</code></a> Update documentation cookie preferences (<a href="https://github-redirect.dependabot.com/boto/boto3/issues/3035">#3035</a>)</li>
<li><a href="/~https://github.com/boto/boto3/commit/31531e1cb774374f8cb49eafe2aa5d8d43c5d41a"><code>31531e1</code></a> Merge branch 'release-1.18.59' into develop</li>
<li>See full diff in <a href="/~https://github.com/boto/boto3/compare/1.18.59...1.18.60">compare view</a></li>
</ul>
</details>
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