[PATCH-for-5.2 2/2] gitlab-ci: Avoid running the EDK2 job when not necessary

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

The EDK2 jobs use the 'changes' keyword, which "makes it
possible to define if a job should be created based on files
modified by a Git push event." (see [1]). This keyword comes
with a warning:

  Caution:

    In pipelines with sources other than the three above
    changes can’t determine if a given file is new or old
    and always returns true."

In commit 922febe2af we moved the YAML config file from the
repository root directory to the .gitlab-ci.d/ directory.

We didn't respect the previous warning and disabled the
'changes' filter rule, as the files are now in a (directory)
three above the YAML config file.

This jobs takes ~40min, and needlessly burns the 2000 minutes
available to GitLab free users. Follow the recommendations in
[3] and disable this job by default (except if we push a tag
or the branch contains 'edk2'). Note we do not remove the job
from the pipeline, it can still be triggered manually from the
WebUI.

[1] https://docs.gitlab.com/ee/ci/yaml/#onlychangesexceptchanges
[2] https://about.gitlab.com/releases/2020/03/18/ci-minutes-for-free-users/
[3] https://about.gitlab.com/pricing/faq-consumption-cicd/

Fixes: 922febe2af ("Move edk2 and opensbi YAML files to .gitlab-ci.d folder")
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 .gitlab-ci.d/edk2.yml | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/.gitlab-ci.d/edk2.yml b/.gitlab-ci.d/edk2.yml
index e1e04524166..335c99035c9 100644
--- a/.gitlab-ci.d/edk2.yml
+++ b/.gitlab-ci.d/edk2.yml
@@ -1,10 +1,5 @@
 docker-edk2:
  stage: containers
- rules: # Only run this job when the Dockerfile is modified
- - changes:
-   - .gitlab-ci.d/edk2.yml
-   - .gitlab-ci.d/edk2/Dockerfile
-   when: always
  image: docker:19.03.1
  services:
  - docker:19.03.1-dind
@@ -26,13 +21,15 @@ docker-edk2:
 build-edk2:
  stage: build
  rules: # Only run this job when ...
- - changes: # ... roms/edk2/ is modified (submodule updated)
-   - roms/edk2/*
+ - if: $CI_COMMIT_TAG # we pushed a tag
    when: always
  - if: '$CI_COMMIT_REF_NAME =~ /^edk2/' # or the branch/tag starts with 'edk2'
    when: always
  - if: '$CI_COMMIT_MESSAGE =~ /edk2/i' # or last commit description contains 'EDK2'
    when: always
+   # ... else allow manual run on the WebUI
+ - when: manual
+   allow_failure: true
  artifacts:
    paths: # 'artifacts.zip' will contains the following files:
    - pc-bios/edk2*bz2
-- 
2.26.2