docs/devel: remind developers to run CI container pipeline when updating images

When new dependencies and packages are added to containers, its important to
run CI container generation pipelines on gitlab to make sure that there are no
obvious conflicts between packages that are being added and those that are
already present. Running CI container pipelines will make sure that there are
no such breakages before we commit the change updating the containers. Add a
line in the documentation reminding developers to run the pipeline before
submitting the change. It will also ease the life of the maintainers.

Signed-off-by: Ani Sinha <anisinha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20230506072012.10350-1-anisinha@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
diff --git a/docs/devel/testing.rst b/docs/devel/testing.rst
index 4071e72..203facb 100644
--- a/docs/devel/testing.rst
+++ b/docs/devel/testing.rst
@@ -479,6 +479,12 @@
    contains the ``mappings.yml`` update.  Then add the prerequisite and
    run ``make lcitool-refresh``.
 
+ * Please also trigger gitlab container generation pipelines on your change
+   for as many OS distros as practical to make sure that there are no
+   obvious breakages when adding the new pre-requisite. Please see
+   `CI <https://www.qemu.org/docs/master/devel/ci.html>`__ documentation
+   page on how to trigger gitlab CI pipelines on your change.
+
 For enterprise distros that default to old, end-of-life versions of the
 Python runtime, QEMU uses a separate set of mappings that work with more
 recent versions.  These can be found in ``tests/lcitool/mappings.yml``.