fix(tpl): remove fixed width from modify date

Different fonts may occupy different width for the modify date element.
As now there are fallback styles for legacy browsers, it is not
necessary to specify a fixed width for the element.

Author: marjune163

src/tpl/assert/main.css

@@ -206,7 +206,6 @@ em {
 }
 
 .item-list .time {
-	width: 10em;
 	color: #999;
 	text-align: right;
 	white-space: nowrap;

src/tpl/assert/main.css.go

@@ -178,7 +178,6 @@ text-align: right;
 color: #666;
 }
 .item-list .time {
-width: 10em;
 color: #999;
 text-align: right;
 white-space: nowrap;