Upgrade to Roxygen 7

Change-Id: I1e31793ab7eb4c32b44522e993949a46984f7313
diff --git a/DESCRIPTION b/DESCRIPTION
index 480a713..8561b4a 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -9,7 +9,7 @@
 License: BSD_2_clause + file LICENSE
 Encoding: UTF-8
 LazyData: false
-RoxygenNote: 6.1.1
+RoxygenNote: 7.0.1
 Imports:
     R.cache,
     broom,