Automatically trigger GitLab Pages pipelines

Whenever master or one for the v9_* branches gets updated, the current
ARM should be published on GitLab Pages.  Add a pipeline stage which
takes care of triggering GitLab Pages pipelines.  Extend the lifetime of
artifact archives containing the ARM to prevent GitLab Pages pipelines
from failing due to artifacts being unavailable.
27 jobs for 565-automatically-trigger-gitlab-pages-pipelines in 9 minutes and 53 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Precheck
passed precheck:debian:sid:amd64 #70393
amd64 docker linux

00:00:21

 
  Build
passed build:centos:centos6:amd64 #70394
amd64 docker linux

00:02:45

passed build:centos:centos7:amd64 #70395
amd64 docker linux

00:02:33

passed build:clang:debian:stretch:amd64 #70396
amd64 docker linux

00:02:02

passed build:clang:debian:stretch:i386 #70400
i386 docker linux

00:02:07

passed build:debian:jessie:amd64 #70397
amd64 docker linux

00:01:37

passed build:debian:sid:amd64 #70399
amd64 docker linux

00:02:28

passed build:debian:sid:i386 #70401
i386 docker linux

00:01:46

passed build:debian:stretch:amd64 #70398
amd64 docker linux

00:01:45

passed pkcs11:build:debian:sid:amd64 #70402
amd64 docker linux

00:02:46

 
  Test
passed docs:debian:sid:amd64 #70403
amd64 docker linux

00:01:00

passed install:debian:sid:amd64 #70417
amd64 docker linux

00:01:55

passed pkcs11:systemtest:debian:sid:amd64 #70419
amd64 docker linux

00:05:12

passed pkcs11:unittest:debian:sid:amd64 #70418
amd64 docker linux

00:00:51

passed systemtest:centos:centos6:amd64 #70411
amd64 docker linux

00:04:57

passed systemtest:centos:centos7:amd64 #70412
docker linux amd64

00:06:21

passed systemtest:debian:jessie:amd64 #70413
amd64 docker linux

00:05:04

passed systemtest:debian:sid:amd64 #70415
amd64 docker linux

00:04:49

passed systemtest:debian:sid:i386 #70416
i386 docker linux

00:06:43

passed systemtest:debian:stretch:amd64 #70414
amd64 docker linux

00:06:31

passed unittest:centos:centos6:amd64 #70404
amd64 docker linux

00:01:02

passed unittest:centos:centos7:amd64 #70405
amd64 docker linux

00:00:52

passed unittest:clang:debian:stretch:amd64 #70409
amd64 docker linux

00:00:42

passed unittest:debian:jessie:amd64 #70406
amd64 docker linux

00:01:03

passed unittest:debian:sid:amd64 #70408
amd64 docker linux

00:00:56

passed unittest:debian:sid:i386 #70410
i386 docker linux

00:00:45

passed unittest:debian:stretch:amd64 #70407
amd64 docker linux

00:00:44