Add alert-link class to migration guide alert link (#738)

Author: tcbegley

docs/templates/partials/migration-guide-alert.html

@@ -1,4 +1,8 @@
-<div id="migration-guide-alert-container" style="display:none" class="mt-3 px-5">
+<div
+  id="migration-guide-alert-container"
+  style="display:none"
+  class="mt-3 px-5"
+>
   <div
     id="migration-guide-alert"
     class="alert alert-warning alert-dismissible mx-auto"
@@ -7,8 +11,8 @@
   >
     You are viewing the documentation for
     <i>dash-bootstrap-components</i> version 1. Please check our
-    <a href="/migration-guide">migration guide</a> if you're upgrading from
-    version 0.13.x.
+    <a href="/migration-guide" class="alert-link">migration guide</a> if you're
+    upgrading from version 0.13.x.
     <button
       type="button"
       class="btn-close"