Update copyrights to 2020.
diff --git a/src/dnsmasq.h b/src/dnsmasq.h
index ce8fbd6..f065132 100644
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2018 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2020 Simon Kelley
  
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -14,7 +14,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#define COPYRIGHT "Copyright (c) 2000-2018 Simon Kelley"
+#define COPYRIGHT "Copyright (c) 2000-2020 Simon Kelley"
 
 /* We do defines that influence behavior of stdio.h, so complain
    if included too early. */