Add missing template argument for c++14 support

6 jobs for feature/assembler_restructure in 35 minutes and 10 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Test
passed #15525
dune-2.6 debian-10 gcc-8-17

00:17:23

passed #15526
dune-2.6 debian-9 gcc-6-14

00:14:28

passed #15527
dune-2.6 ubuntu-18.04 clang-6-17

00:11:45

passed #15528
dune-git debian-10 gcc-8-17

00:27:30

passed #15529
dune-git debian-9 gcc-6-14

00:19:40

passed #15530
dune-git ubuntu-18.04 clang-6-17

00:17:43