Snakefile: fix caching in fetch_epic (#78)

Snakefile

@@ -34,6 +34,9 @@ def get_remote_path(path):
 rule fetch_epic:
     output:
         filepath="EPIC/{PATH}"
+    params:
+        # wildcards are not included in hash for caching, we need to add them as params
+        PATH=lambda wildcards: wildcards.PATH
     cache: True
     retries: 3
     shell: """