Update license text in README

README

@@ -49,17 +49,15 @@ AUTHOR
     Yoshiki Kurihara <[email protected]> Copyright (C) 2010 by Free Software
     Foundation, Inc.
 
-    This file is free software; you can redistribute it and/or modify it
-    under the terms of the GNU General Public License as published by the
-    Free Software Foundation; either version 2, or (at your option) any
-    later version.
-
-    This file is distributed in the hope that it will be useful, but WITHOUT
-    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
-    more details.
-
-    You should have received a copy of the GNU General Public License along
-    with GNU Emacs; see the file COPYING. If not, write to the Free Software
-    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
-    USA.
+    This file is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This file is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.