ease
type (<code>major</code>,   <code>premajor</code>, <code>minor</code>, <code>preminor</code>, <code>patch</code>,
<code>prepatch</code>, or <code>prerelease</code>), or null if it&#39;s not valid<ul>
<li><code>premajor</code> in one call will bump the version up to the next major
version and down to a prerelease of that major version.
<code>preminor</code>, and <code>prepatch</code> work the same way.</li>
<li>If called from a non-prerelease version, the <code>prerelease</code> will work the
same as <c