Backport PR #48770 on branch 1.5.x (added sytle in stylesheet for <blockquote>) (#49102)

Backport PR #48770: added sytle in stylesheet for <blockquote>

Co-authored-by: Himanshu Wagh <[email protected]>

Author: meeseeksmachine

web/pandas/static/css/pandas.css

@@ -96,3 +96,10 @@ table.logo td {
 table.logo img {
     height: 4rem;
 }
+blockquote {
+    background: #f9f9f9;
+    border-left: 5px solid #ccc;
+    padding-left:15px;
+    color: #787878;
+    font-size: 18px;
+ }