[interchange] Correct typo

[Jon Jensen]

commit 6c8dea80496d1d3421ca0bec77012ada9246270e
Author: Jon Jensen <jon at endpoint.com>
Date:   Thu Feb 9 18:24:57 2017 -0700

    Correct typo

 UPGRADE |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/UPGRADE b/UPGRADE
index 005f255..c5f8cc7 100644
--- a/UPGRADE
+++ b/UPGRADE
@@ -91,7 +91,7 @@ KNOWN ISSUES UPGRADING FROM 5.10.x
 
 1.  A bug was fixed in the [area] tag where if you previously passed a fully
 qualified URL as the href and used the form attribute then the protocol://domain
-portion of the URL would get overwritten by the one in VendUrl.  If you're code
+portion of the URL would get overwritten by the one in VendUrl. If your code
 relies on this buggy behaviour you need to fix it.