main: Update copyright notice with year 2018

Change-Id: I2d80bc5edf940fab914cba3d8a0fa0b5eb2a3148

main/asterisk.c

@@ -1,7 +1,7 @@
 /*
  * Asterisk -- An open source telephony toolkit.
  *
- * Copyright (C) 1999 - 2016, Digium, Inc.
+ * Copyright (C) 1999 - 2018, Digium, Inc.
  *
  * Mark Spencer <markster@digium.com>
  *
@@ -53,7 +53,7 @@
  *
  * \section copyright Copyright and Author
  *
- * Copyright (C) 1999 - 2016, Digium, Inc.
+ * Copyright (C) 1999 - 2018, Digium, Inc.
  * Asterisk is a <a href="http://www.digium.com/en/company/view-policy.php?id=Trademark-Policy">registered trademark</a>
  * of <a rel="nofollow" href="http://www.digium.com">Digium, Inc</a>.
  *
@@ -300,7 +300,7 @@ int daemon(int, int);  /* defined in libresolv of all places */
 
 /*! \brief Welcome message when starting a CLI interface */
 #define WELCOME_MESSAGE \
-    ast_verbose("Asterisk %s, Copyright (C) 1999 - 2016, Digium, Inc. and others.\n" \
+    ast_verbose("Asterisk %s, Copyright (C) 1999 - 2018, Digium, Inc. and others.\n" \
                 "Created by Mark Spencer <markster@digium.com>\n" \
                 "Asterisk comes with ABSOLUTELY NO WARRANTY; type 'core show warranty' for details.\n" \
                 "This is free software, with components licensed under the GNU General Public\n" \