Fix history width

Author: barryvdh

src/DebugBar/Resources/debugbar.css

@@ -316,7 +316,7 @@ div.phpdebugbar-mini-design a.phpdebugbar-tab {
 /* -------------------------------------- */
 
   a.phpdebugbar-tab.phpdebugbar-tab-history {
-    width: 16px;
+    min-width: 16px;
     height: 16px;
     display: flex;
     justify-content: center;