update xml2 version requirement as reported in #17
diff --git a/DESCRIPTION b/DESCRIPTION
index eba392d..5cb8ec3 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -33,7 +33,7 @@
     knitr (>= 1.16),
     magrittr,
     stringr (>= 1.0),
-    xml2,
+    xml2 (>= 1.1.1),
     rvest,
     rmarkdown (>= 1.6.0),
     readr,