docs(toasts): centered examples flexbugs #3 in IE11

Author: ffoodd

site/docs/4.5/components/toasts.md

@@ -167,7 +167,7 @@ You can also get fancy with flexbox utilities to align toasts horizontally and/o
 
 {% capture example %}
 <!-- Flexbox container for aligning the toasts -->
-<div aria-live="polite" aria-atomic="true" class="d-flex justify-content-center align-items-center" style="min-height: 200px;">
+<div aria-live="polite" aria-atomic="true" class="d-flex justify-content-center align-items-center" style="height: 200px;">
 
   <!-- Then put toasts within -->
   <div class="toast" role="alert" aria-live="assertive" aria-atomic="true">