Add CRAN-SUBMISSION to .Rbuildignore

Change-Id: Ib59e5e7fe9c072a06fe3d7bfec278432a9eec02d
diff --git a/.Rbuildignore b/.Rbuildignore
index b0160d1..812333a 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -9,3 +9,4 @@
 ^_pkgdown\.yml$
 ^CRAN-RELEASE$
 ^.*\.log$
+^CRAN-SUBMISSION$