Increase form input field border contrast

The contrast provided by the border-gray-200 Tailwind utility
class is very poor. It's nearly impossible to distinguish the edges 
of an input field on a white background. 

That's not a great default experience for Rails scaffolds.

With a slight bump to border-gray-400, things are much easier 
to distinguish.

lib/generators/tailwindcss/scaffold/templates/_form.html.erb.tt

@@ -15,23 +15,23 @@
   <div class="my-5">
 <% if attribute.password_digest? -%>
     <%%= form.label :password %>
-    <%%= form.password_field :password, class: "block shadow rounded-md border border-gray-200 outline-none px-3 py-2 mt-2 w-full" %>
+    <%%= form.password_field :password, class: "block shadow rounded-md border border-gray-400 outline-none px-3 py-2 mt-2 w-full" %>
 </div>
 
 <div class="my-5">
     <%%= form.label :password_confirmation %>
-    <%%= form.password_field :password_confirmation, class: "block shadow rounded-md border border-gray-200 outline-none px-3 py-2 mt-2 w-full" %>
+    <%%= form.password_field :password_confirmation, class: "block shadow rounded-md border border-gray-400 outline-none px-3 py-2 mt-2 w-full" %>
 <% elsif attribute.attachments? -%>
     <%%= form.label :<%= attribute.column_name %> %>
-    <%%= form.<%= attribute.field_type %> :<%= attribute.column_name %>, multiple: true, class: "block shadow rounded-md border border-gray-200 outline-none px-3 py-2 mt-2 w-full" %>
+    <%%= form.<%= attribute.field_type %> :<%= attribute.column_name %>, multiple: true, class: "block shadow rounded-md border border-gray-400 outline-none px-3 py-2 mt-2 w-full" %>
 <% else -%>
     <%%= form.label :<%= attribute.column_name %> %>
 <% if attribute.field_type == :text_area -%>
-    <%%= form.<%= attribute.field_type %> :<%= attribute.column_name %>, rows: 4, class: "block shadow rounded-md border border-gray-200 outline-none px-3 py-2 mt-2 w-full" %>
+    <%%= form.<%= attribute.field_type %> :<%= attribute.column_name %>, rows: 4, class: "block shadow rounded-md border border-gray-400 outline-none px-3 py-2 mt-2 w-full" %>
 <% elsif attribute.field_type == :check_box -%>
     <%%= form.<%= attribute.field_type %> :<%= attribute.column_name %>, class: "block mt-2 h-5 w-5" %>
 <% else -%>
-    <%%= form.<%= attribute.field_type %> :<%= attribute.column_name %>, class: "block shadow rounded-md border border-gray-200 outline-none px-3 py-2 mt-2 w-full" %>
+    <%%= form.<%= attribute.field_type %> :<%= attribute.column_name %>, class: "block shadow rounded-md border border-gray-400 outline-none px-3 py-2 mt-2 w-full" %>
 <% end -%>
 <% end -%>
   </div>