Fix license statement with old FSF address

Signed-off-by: Stefan Weil <sw@weilnetz.de>

autopostgresqlbackup

@@ -17,8 +17,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+# along with this program; if not, see
+# <https://www.gnu.org/licenses/>.
 # }}}
 
 # {{{ Constants