Remove packaging dependency

Closes #323

Author: jeromekelleher

bio2zarr/zarr_utils.py

@@ -1,9 +1,8 @@
 import zarr
-from packaging.version import Version
 
 
 def zarr_v3() -> bool:
-    return Version(zarr.__version__).major >= 3
+    return zarr.__version__ >= "3"
 
 
 if zarr_v3():

pyproject.toml

@@ -23,7 +23,6 @@ dependencies = [
   # colouredlogs pulls in humanfriendly",
   "cyvcf2",
   "bed_reader",
-  "packaging",
 ]
 requires-python = ">=3.9"
 classifiers = [