Bump ajv from 6.10.2 to 6.12.6

Bumps [ajv](https://github.com/ajv-validator/ajv) from 6.10.2 to 6.12.6.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/ajv-validator/ajv/releases">ajv's releases</a>.</em></p>
<blockquote>
<h2>v6.12.6</h2>
<p>Fix performance issue of &quot;url&quot; format.</p>
<h2>v6.12.5</h2>
<p>Fix uri scheme validation (<a href="https://github.com/ChALkeR"><code>@​ChALkeR</code></a>).
Fix boolean schemas with strictKeywords option (<a href="https://github-redirect.dependabot.com/ajv-validator/ajv/issues/1270">#1270</a>)</p>
<h2>v6.12.4</h2>
<p>Fix: coercion of one-item arrays to scalar that should fail validation (<a href="https://runkit.com/esp/5f3672ba2f6642001ae27411">failing example</a>).</p>
<h2>v6.12.3</h2>
<p>Pass schema object to processCode function
Option for strictNumbers (<a href="https://github.com/issacgerges"><code>@​issacgerges</code></a>, <a href="https://github-redirect.dependabot.com/ajv-validator/ajv/issues/1128">#1128</a>)
Fixed vulnerability related to untrusted schemas (<a href="https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2020-15366">CVE-2020-15366</a>)</p>
<h2>v6.12.2</h2>
<p>Removed post-install script</p>
<h2>v6.12.1</h2>
<p>Docs and dependency updates</p>
<h2>v6.12.0</h2>
<p>Improved hostname validation (<a href="https://github.com/sambauers"><code>@​sambauers</code></a>, <a href="https://github-redirect.dependabot.com/ajv-validator/ajv/issues/1143">#1143</a>)
Option <code>keywords</code> to add custom keywords (<a href="https://github.com/franciscomorais"><code>@​franciscomorais</code></a>, <a href="https://github-redirect.dependabot.com/ajv-validator/ajv/issues/1137">#1137</a>)
Types fixes (<a href="https://github.com/boenrobot"><code>@​boenrobot</code></a>, <a href="https://github.com/MattiAstedrone"><code>@​MattiAstedrone</code></a>)
Docs:</p>
<ul>
<li><a href="https://github.com/epoberezkin/ajv#error-logging">error logging</a> example (<a href="https://github.com/RadiationSickness"><code>@​RadiationSickness</code></a>)</li>
<li>TypeScript usage notes (<a href="https://github.com/thetric"><code>@​thetric</code></a>)</li>
</ul>
<h2>v6.11.0</h2>
<p>Time formats support two digit and colon-less variants of timezone offset (<a href="https://github-redirect.dependabot.com/ajv-validator/ajv/issues/1061">#1061</a> , <a href="https://github.com/cjpillsbury"><code>@​cjpillsbury</code></a>)
Docs: RegExp related security considerations
Tests: Disabled failing typescript test</p>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/ajv-validator/ajv/commit/fe591439f34e24030f69df9eb8d91e6d037a3af7"><code>fe59143</code></a> 6.12.6</li>
<li><a href="https://github.com/ajv-validator/ajv/commit/d580d3e8ac6a467670d68d86e3a39fd661ac8c23"><code>d580d3e</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/ajv-validator/ajv/issues/1298">#1298</a> from ajv-validator/fix-url</li>
<li><a href="https://github.com/ajv-validator/ajv/commit/fd363896a8d6c5697b5da41f4d9a400a84efaf8e"><code>fd36389</code></a> fix: regular expression for &quot;url&quot; format</li>
<li><a href="https://github.com/ajv-validator/ajv/commit/490e34c4846064db5c962a77087e17078954c2f6"><code>490e34c</code></a> docs: link to v7-beta branch</li>
<li><a href="https://github.com/ajv-validator/ajv/commit/9cd93a1bdbdefd5a7ba3db5e123d20c84d1d1d0e"><code>9cd93a1</code></a> docs: note about v7 in readme</li>
<li><a href="https://github.com/ajv-validator/ajv/commit/877d286e7f145b1b2127da66c6800b071533f28f"><code>877d286</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/ajv-validator/ajv/issues/1262">#1262</a> from b4h0-c4t/refactor-opt-object-type</li>
<li><a href="https://github.com/ajv-validator/ajv/commit/f1c8e45b9cdff918be28becf03bf0b339321c398"><code>f1c8e45</code></a> 6.12.5</li>
<li><a href="https://github.com/ajv-validator/ajv/commit/764035e201d7733b8d700d4a04dd079fef9f4d30"><code>764035e</code></a> Merge branch 'ChALkeR-chalker/fix-comma'</li>
<li><a href="https://github.com/ajv-validator/ajv/commit/37981602ce6d43313ae106644b372b021626a8af"><code>3798160</code></a> Merge branch 'chalker/fix-comma' of git://github.com/ChALkeR/ajv into ChALkeR...</li>
<li><a href="https://github.com/ajv-validator/ajv/commit/a3c7ebab222e4cce07b5e30ebcbb809da7f934e8"><code>a3c7eba</code></a> Merge branch 'refactor-opt-object-type' of github.com:b4h0-c4t/ajv into refac...</li>
<li>Additional commits viewable in <a href="https://github.com/ajv-validator/ajv/compare/v6.10.2...v6.12.6">compare view</a></li>
</ul>
</details>
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