replatform: author page is missing tags

[cantsin]

Example: /author/julia-lindpaintner/

We are missing tags for each of these posts. They seem to show up elsewhere, notably on the actual blog post. (`/2019/05/29/you-might-not-be-as-agile-as-you-think-you-are/)

<          <a class="usa-label post-tag" href="/tags/agile/">
<           agile
<          </a>
<          <a class="usa-label post-tag" href="/tags/lessons-learned/">
<           lessons learned
<          </a>
<          <a class="usa-label post-tag" href="/tags/best-practices/">
<           best practices
<          </a>

[beechnut]

Added to #4050