Remove packbits default for bool

As discussed in
#74 (comment)

Author: jeromekelleher

bio2zarr/vcf.py

@@ -1231,8 +1231,6 @@ def _choose_compressor_settings(self):
             shuffle = numcodecs.Blosc.BITSHUFFLE
         self.compressor["shuffle"] = shuffle
 
-        if dt.name == "bool":
-            self.filters.append(numcodecs.PackBits().get_config())
 
 
 ZARR_SCHEMA_FORMAT_VERSION = "0.2"