update description

Author: dfalbel

DESCRIPTION

@@ -3,7 +3,8 @@ Type: Package
 Title: R Interface to 'TensorFlow'
 Version: 1.13.1
 Authors@R: c(
-  person("JJ", "Allaire", role = c("aut", "cre"), email = "[email protected]"),
+  person("Daniel", "Falbel", role = c("ctb", "cph", "cre"), email = "[email protected]"),
+  person("JJ", "Allaire", role = c("aut", "cph")),
   person(family = "RStudio", role = c("cph", "fnd")),
   person("Yuan", "Tang", role = c("aut", "cph"),
          email = "[email protected]",