Put Author, Assignee, Created on newline

These header fields are easier to read if they are on
separate lines.

Tested: Copied into https://jbt.github.io/markdown-editor
Change-Id: Ibcd204f21d40c99ccce14cc97947c212ccc337b5
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/designs/design-template.md b/designs/design-template.md
index c730132..892e01e 100644
--- a/designs/design-template.md
+++ b/designs/design-template.md
@@ -27,10 +27,13 @@
 
 Author:
   < Name and IRC nic >
+
 Primary assignee:
   < Name and/or IRC nic or None >
+
 Other contributors:
   < Name and/or IRC nic or None >
+
 Created:
   < Date initially created, revisions in will be tracked in Gerrit >