Merge pull request #255 from EESSI/nested_catalog_per_version

add nested catalog for each EESSI version

Author: boegel

roles/create_cvmfs_content_structure/files/.cvmfsdirtab

@@ -1,3 +1,6 @@
+# Nested catalog for each EESSI version
+/versions/*
+
 # Compatibility layer paths:
 # /versions/<version>/compat/{linux,macos}/{aarch64,riscv64,x86_64}
 /versions/*/compat/*/*