[GR-2798] Update the copyright years in the initial message.

PullRequest: fastr/1986

Author: steve-s

com.oracle.truffle.r.runtime/src/com/oracle/truffle/r/runtime/RRuntime.java

@@ -68,9 +68,9 @@ public class RRuntime {
     // Parts of the welcome message originate from GNU R.
     public static final String WELCOME_MESSAGE =
         "R version " + RVersionNumber.FULL + " (FastR)\n" +
-        "Copyright (c) 2013-18, Oracle and/or its affiliates\n" +
-        "Copyright (c) 1995-2017, The R Core Team\n" +
-        "Copyright (c) 2017 The R Foundation for Statistical Computing\n" +
+        "Copyright (c) 2013-19, Oracle and/or its affiliates\n" +
+        "Copyright (c) 1995-2018, The R Core Team\n" +
+        "Copyright (c) 2018 The R Foundation for Statistical Computing\n" +
         "Copyright (c) 2012-4 Purdue University\n" +
         "Copyright (c) 1997-2002, Makoto Matsumoto and Takuji Nishimura\n" +
         "All rights reserved.\n" +