Improve the variables passed in trigger-build

Make the variable names consistent by following the
`TOP_UPSTREAM_SOURCE_*` pattern.

Signed-off-by: Rémy Coutable <remy@rymai.me>

scripts/trigger-build

@@ -68,12 +68,11 @@ module Trigger
     def base_variables
       {
-        'TOP_UPSTREAM_TRIGGER_PROJECT' => ENV['TOP_UPSTREAM_TRIGGER_PROJECT'] || ENV['CI_PROJECT_PATH'],
-        'TOP_UPSTREAM_SOURCE_SHA' => ENV['CI_COMMIT_SHA'],
-        'UPSTREAM_TRIGGER_PROJECT' => ENV['CI_PROJECT_PATH'],
-        'UPSTREAM_TRIGGER_SOURCE' => ENV['TRIGGER_SOURCE'],
         'TRIGGERED_USER' => ENV['TRIGGERED_USER'] || ENV['GITLAB_USER_NAME'],
-        'TRIGGER_SOURCE' => ENV['CI_JOB_URL']
+        'TRIGGER_SOURCE' => ENV['CI_JOB_URL'],
+        'TOP_UPSTREAM_SOURCE_PROJECT' => ENV['CI_PROJECT_PATH'],
+        'TOP_UPSTREAM_SOURCE_JOB' => ENV['CI_JOB_URL'],
+        'TOP_UPSTREAM_SOURCE_SHA' => ENV['CI_COMMIT_SHA']
       }
     end