Be capable of running build vs upload

.gitlab-ci-build.yml.in

@@ -15,9 +15,11 @@ stages:
     - if: $CI_COMMIT_TAG
       variables:
         EXCEPT: ''
+        JOB_PREFIX: 'ci'
     - if: $CI_COMMIT_TAG =~ "/^$/"
       variables:
         EXCEPT: '-except=upload'
+        JOB_PREIX: 'upload'
   needs:
     - pipeline: $PARENT_PIPELINE_ID
       job: continue
@@ -32,7 +34,7 @@ stages:
     PACKER_CACHE_DIR: ./cache/
     PACKER_LOG: 1
   script:
-    - nix run ".#\"${buildcmd}\"" || exit 1
+    - nix run ".#\"${JOB_PREIX}${buildcmd}\"" || exit 1
 
 qemu.amd64:
   extends: .build