The address of the Free Software Foundation has changed since the
license was added in 7640d90b

 ("Add license file and copyright notices",
2006-12-10).  Update the license file from gnu.org¹.

The only non-whitespace changes are the updated FSF address and two
references to the L in LGPL changed from Library to Lesser.

¹ https://www.gnu.org/licenses/old-licenses/gpl-2.0.txt

Signed-off-by: Todd Zullinger <tmz@pobox.com>