gitlab: Keep Avocado reports during 1 week

Sometimes pull requests are merged during the week-end, triggering
a CI pipeline. Currently if such pipeline fails, the Avocado reports
are available for 2 days. For the reviewers working on the project
during office hours, the reports are already discarded when they
want to look at them. Increase this time to 1 week, which should
give reviewers enough time.

Only keep the reports on failure, which is the only case we'll
look at them.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210525082556.4011380-8-f4bug@amsat.org>

.gitlab-ci.d/buildtest-template.yml

@@ -46,8 +46,8 @@
     policy: pull-push
   artifacts:
     name: "$CI_JOB_NAME-$CI_COMMIT_REF_SLUG"
-    when: always
-    expire_in: 2 days
+    when: on_failure
+    expire_in: 7 days
     paths:
       - build/tests/results/latest/results.xml
       - build/tests/results/latest/test-results