pg_upgrade: Bump MESSAGE_WIDTH.

Commit 7b37823 added a status message to pg_upgrade that is 60
characters wide.  Since the MESSAGE_WIDTH macro is currently set to
60, there is no space between this new status message and the "ok"
or "failed" indicator appended when the step completes.  To fix
this problem, this commit increases the value of MESSAGE_WIDTH to
62.

Suggested-by: Bharath Rupireddy
Reviewed-by: Peter Eisentraut
Discussion: https://postgr.es/m/CALj2ACVVvk1cYLtWVxHv%3DZ1Ubq%3DUES9fhKbUU4c9k4W%2BfEDnbw%40mail.gmail.com
Backpatch-through: 16

Author: nathan-bossart

src/bin/pg_upgrade/pg_upgrade.h

@@ -22,7 +22,7 @@
 #define MAX_STRING			1024
 #define QUERY_ALLOC			8192
 
-#define MESSAGE_WIDTH		60
+#define MESSAGE_WIDTH		62
 
 #define GET_MAJOR_VERSION(v)	((v) / 100)