add py-elephant to spack.yml

spack.yaml

@@ -44,6 +44,7 @@ spack:
     - py-hbp-neuromorphic-platform@0.10.1
     - py-torch~cuda~rocm~valgrind~mkldnn~mpi~gloo~tensorpipe~onnx_ml@1.9.1 ^protobuf@:3.17.999
     - py-lfpy@2.2.6
+    - py-elephant
     #- biobb-common
     # demo for codejam12
     #- funniest1022