another attempt at fixing travis build error
diff --git a/DESCRIPTION b/DESCRIPTION
index 788a456..a6f6138 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -19,5 +19,5 @@
 URL: https://github.com/brentthorne/posterdown
 BugReports: https://github.com/brentthorne/posterdown/issues
 Imports: bookdown, ggplot2, pagedown, kableExtra, Cairo, rmarkdown, knitr, yaml, ggspatial
-SystemRequirements: GNU make
+SystemRequirements: GNU make, Pandoc (>= 2.2.3)
 RoxygenNote: 6.1.1