Remove knot tag from Gitlab CI

6 jobs for master in 5 minutes and 25 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Configure
passed #7931
docker linux amd64
configure:debian:stretch:amd64

00:01:06

passed #7930
docker linux amd64
configure:ubuntu:amd64

00:02:10

 
  Build
passed #7933
docker linux amd64
build:debian:stretch:amd64

00:02:19

passed #7932
docker linux amd64
build:ubuntu:amd64

00:02:17

 
  Test
passed #7935
docker linux amd64
test:debian:stretch:amd64

00:00:51

passed #7934
docker linux amd64
test:ubuntu:amd64

00:00:56