replaced PosixPath and WindowsPath with pathlib.Path

following suggestion by @djhoese

satpy/readers/__init__.py

@@ -20,9 +20,9 @@
 
 import logging
 import os
+import pathlib
 import pickle  # nosec B403
 import warnings
-import pathlib
 from datetime import datetime, timedelta
 from functools import total_ordering
 
@@ -780,7 +780,7 @@ def _get_compression(file):
 
 def open_file_or_filename(unknown_file_thing):
     """Try to open the *unknown_file_thing*, otherwise return the filename."""
-    if isinstance(unknown_file_thing, (pathlib.WindowsPath, pathlib.PosixPath)):
+    if isinstance(unknown_file_thing, pathlib.Path):
         f_obj = unknown_file_thing
     else:
         try:

satpy/readers/hdf5_utils.py

@@ -24,10 +24,10 @@
 import numpy as np
 import xarray as xr
 
+from satpy.readers import open_file_or_filename
 from satpy.readers.file_handlers import BaseFileHandler
 from satpy.readers.utils import np2str
 from satpy.utils import get_legacy_chunk_size
-from satpy.readers import open_file_or_filename
 
 LOG = logging.getLogger(__name__)
 CHUNK_SIZE = get_legacy_chunk_size()