Fix input/select heights across all browsers (#6686)

Author: nlhkabu

warehouse/static/sass/base/_forms.scss

@@ -19,7 +19,7 @@ select {
   font-size: $input-font-size;
   border-radius: 2px;
   background-color: $white;
-  padding: 0 8px;
+  padding: 7px;
   min-height: 40px;
   border: 1px solid $accessible-border-color;
   color: $text-color;