Mark msgpack as a separate dependency

Author: agriyakhetarpal

pyproject.toml

@@ -16,7 +16,8 @@ dependencies = [
     'numpy>=1.23',
     'fasteners; sys_platform != "emscripten"',
     'numcodecs>=0.10.0',
-    'numcodecs[msgpack]>=0.10.0; sys_platform == "emscripten"',
+    'numcodecs[msgpack]>=0.10.0; sys_platform == "emscripten"',  # TODO: can be removed
+    'msgpack; sys_platform == "emscripten"',
 ]
 dynamic = [
   "version",