Devops: Add the slurm service to nightly workflow (#6372)

The nightly worklow is configuring a computer that is using the
`core.slurm` scheduler plugin, however, the container did not have a
SLURM service running.

.github/workflows/nightly.yml

@@ -49,6 +49,10 @@ jobs:
         ports:
         - 5672:5672
         - 15672:15672
+      slurm:
+        image: xenonmiddleware/slurm:17
+        ports:
+        - 5001:22
 
     steps:
     - uses: actions/checkout@v4