update license file

5 jobs for v2.6.0 in 50 minutes and 28 seconds (queued for 78 minutes)
latest
Status Job ID Name Coverage
  Test
passed #32725
duneci
debian:10 gcc:c++17

00:12:49

passed #32727
duneci
debian:9--clang

00:10:22

passed #32726
duneci
debian:9--gcc

00:08:50

passed #32729
duneci
ubuntu:16.04--clang

00:10:17

passed #32728
duneci
ubuntu:16.04--gcc

00:08:09