Modified the year in the license

I edited the license.
4 jobs for 137-license_update in 1 minute and 33 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #1691
Go-py2.7

00:01:30

passed #1692
Go-py3.4

00:01:26

passed #1693
Go-py3.5

00:01:32

passed #1694
Go-py3.6

00:01:32

56.0%