update dates

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2009-2011 Dave Vasilevsky
+Copyright (c) 2009-2020 Dave Vasilevsky
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

src/pixz.1.asciidoc

@@ -85,7 +85,7 @@ Source downloads: <https://github.com/vasi/pixz/releases/>
 
 COPYRIGHT
 ---------
-Copyright (C) 2009-2010 Dave Vasilevsky. Use of this software is granted under the FreeBSD License.
+Copyright (C) 2009-2020 Dave Vasilevsky. Use of this software is granted under the FreeBSD License.
 
 SEE ALSO
 --------

src/pixz.c

@@ -47,7 +47,7 @@ static void usage(const char *msg) {
 "  -h                 Print this help\n"
 "\n"
 "pixz %s\n"
-"(C) 2009-2012 Dave Vasilevsky <dave@vasilevsky.ca>\n"
+"(C) 2009-2020 Dave Vasilevsky <dave@vasilevsky.ca>\n"
 "https://github.com/vasi/pixz\n"
 "You may use this software under the FreeBSD License\n",
 	    PACKAGE_VERSION);