Fix spelling of variable name in CI config

.gitlab-ci.yml

@@ -67,7 +67,7 @@ automated_test:
     - export LANG=C  # Hopefully detect anything relying on locale
     - python3 -m pip install ".[automated_test]"
     - echo "Running automated test. This can take sometime to finish depending on the test data."
-    - echo "Given variables are REFERENCE=$REFERENCE, OUTPUT=$OUTPUT, DETECTOR=$DETECTORS, CALIBRATION=$CALIBRATION"
+    - echo "Given variables are REFERENCE=$REFERENCE, OUTPUT=$OUTPUT, DETECTORS=$DETECTORS, CALIBRATION=$CALIBRATION"
     - python3 -m pytest ./tests/test_reference_runs --color yes --verbose --release-test --reference-folder /gpfs/exfel/data/scratch/xcaltst/test/$REFERENCE --out-folder /gpfs/exfel/data/scratch/xcaltst/test/$OUTPUT  --detectors $DETECTORS --calibration $CALIBRATION  --find-difference
   timeout: 24 hours