Release v4.3.0 (#28228)

* Prep for v4.3.0

* More updates for v4.3.0.

* rerun to build docs source map

site/docs/4.3/about/team.md

@@ -0,0 +1,21 @@
+---
+layout: docs
+title: Team
+description: An overview of the founding team and core contributors to Bootstrap.
+group: about
+---
+
+Bootstrap is maintained by the founding team and a small group of invaluable core contributors, with the massive support and involvement of our community.
+
+<div class="list-group mb-3">
+  {% for member in site.data.core-team %}
+    <a class="list-group-item list-group-item-action d-flex align-items-center" href="https://github.com/{{ member.user }}">
+      <img src="https://github.com/{{ member.user }}.png" alt="@{{ member.user }}" width="32" height="32" class="rounded mr-2">
+      <span>
+        <strong>{{ member.name }}</strong> @{{ member.user }}
+      </span>
+    </a>
+  {% endfor %}
+</div>
+
+Get involved with Bootstrap development by [opening an issue]({{ site.repo }}/issues/new) or submitting a pull request. Read our [contributing guidelines]({{ site.repo }}/blob/v{{ site.current_version }}/.github/CONTRIBUTING.md) for information on how we develop.