Align milestone column header with count number

app/assets/stylesheets/framework/panels.scss

@@ -18,6 +18,20 @@
       margin-top: -2px;
       margin-left: 5px;
     }
+
+    &.split {
+      display: flex;
+      align-items: center;
+    }
+
+    .left {
+      flex: 1 1 auto;
+    }
+
+    .right {
+      flex: 0 0 auto;
+      text-align: right;
+    }
   }
 
   .panel-body {

app/views/shared/milestones/_issuables.html.haml

@@ -3,10 +3,12 @@
 - panel_class = primary ? 'panel-primary' : 'panel-default'
 
 .panel{ class: panel_class }
-  .panel-heading
-    = title
+  .panel-heading.split
+    .left
+      = title
     - if show_counter
-      .pull-right= issuables.size
+      .right
+        = issuables.size
 
   - class_prefix = dom_class(issuables).pluralize
   %ul{ class: "well-list #{class_prefix}-sortable-list", id: "#{class_prefix}-list-#{id}", "data-state" => id }