Only include authors if not null

Author: tcompa

fractal_tasks_core/__FRACTAL_MANIFEST__.json

@@ -1,6 +1,5 @@
 {
   "manifest_version": "2",
-  "authors": "Name FIXME, Name FIXME, Name FIXME",
   "task_list": [
     {
       "name": "Convert Cellvoyager to OME-Zarr",
@@ -1548,5 +1547,6 @@
     }
   ],
   "has_args_schemas": true,
-  "args_schema_version": "pydantic_v2"
+  "args_schema_version": "pydantic_v2",
+  "authors": "Name FIXME, Name FIXME, Name FIXME"
 }

fractal_tasks_core/dev/create_manifest.py

@@ -72,12 +72,13 @@ def create_manifest(
     # Prepare an empty manifest
     manifest = dict(
         manifest_version=manifest_version,
-        authors=authors,
         task_list=[],
         has_args_schemas=has_args_schemas,
     )
     if has_args_schemas:
         manifest["args_schema_version"] = ARGS_SCHEMA_VERSION
+    if authors is not None:
+        manifest["authors"] = authors
 
     # Prepare a default value of docs_link
     if package == "fractal_tasks_core" and docs_link is None: