fix: correct variables definition

Author: veprbl

.gitlab-ci.yml

@@ -620,8 +620,7 @@ eic_xl:singularity:nightly:
 .benchmarks:default:
   extends: .benchmarks
   variables:
-    - BUILD_TYPE: default
-    - !reference ['.benchmarks', variables]
+    BUILD_TYPE: default
   needs: 
     - job: version
     - job: eic
@@ -639,8 +638,7 @@ eic_xl:singularity:nightly:
 .benchmarks:nightly:
   extends: .benchmarks
   variables:
-    - BUILD_TYPE: nightly
-    - !reference ['.benchmarks', variables]
+    BUILD_TYPE: nightly
   needs: 
     - job: version
     - job: eic