Add logging to StoreToZarr

#656 
I also added the full target here, because that might be helpful to have?

pangeo_forge_recipes/transforms.py

@@ -547,6 +547,7 @@ def expand(
                 | beam.Map(self.dynamic_chunking_fn, **self.dynamic_chunking_fn_kwargs)
             )
         )
+        logger.warn(f"Storing Zarr with {target_chunks =} to {self.get_full_target()}")
         rechunked_datasets = indexed_datasets | Rechunk(target_chunks=target_chunks, schema=schema)
         target_store = schema | PrepareZarrTarget(
             target=self.get_full_target(),