[gjs/ci-use-mozjs-latest: 2/4] ci: Reuse previous image as base

[Marco Trevisan <marcotrevi src gnome org>]

commit 50b606335605173ded37314dceeaf5d0717eff77
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Mon Oct 12 14:53:47 2020 +0200

    ci: Reuse previous image as base
    
    This avoids to reinstall components that we already have installed in
    previous builds.

 .gitlab-ci.yml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d0087e92..9cc5e29e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -306,7 +306,7 @@ zeal_11:
 #          Create CI Docker Images          #
 #############################################
 .Docker image template: &create_docker_image
-  image: registry.fedoraproject.org/fedora:32
+  image: $IMAGE_BASE
   stage: deploy
   only:
     variables:
@@ -337,6 +337,9 @@ zeal_11:
 .Docker variables: &docker_variables
   IMAGE_NAME: $CI_REGISTRY_IMAGE:$CI_JOB_NAME
   IMAGE_JOB_NAME: CI_REGISTRY_IMAGE:job-${CI_JOB_ID}_$CI_JOB_NAME
+  # May need to set this manually to to registry.fedoraproject.org/fedora:32
+  # when a new image image build is added.
+  IMAGE_BASE: $IMAGE_NAME
   STORAGE_DRIVER: vfs
   BUILDAH_FORMAT: docker
   BUILDAH_ISOLATION: chroot