remove character in envs/MetaSnk.yaml that caused error while creating environment

envs/MetaSnk.yaml

 name: MetaSnk
 channels:
   - defaults
-dependencies:cat 
+dependencies:
   - snakemake=5.5.0
   - matplotlib=3.1.0=py36h5429711_0
   - numpy=1.16.4=py36h7e9f1db_0