deprecate time datatype (#467)

time datatype is deprecated and broken according to https://docs.h5py.org/en/stable/special.html#storing-other-types-as-opaque-data

Co-authored-by: Dani Pinyol <dani@avatarcognition.com>

src/datatypes.jl

@@ -110,7 +110,7 @@ macro read_datatype(io, datatype_class, datatype, then)
         elseif $datatype_class << 4 == DT_BITFIELD << 4
             $(replace_expr(then, datatype, :(jlread($io, BitFieldDatatype))))
         elseif $datatype_class << 4 == DT_TIME << 4
-            $(replace_expr(then, datatype, :(jlread($io, TimeDatatype))))
+            throw(UnsupportedFeatureException("Time datatype (rarely used) not supported"))
         elseif $datatype_class << 4 == DT_ARRAY << 4
             $(replace_expr(then, datatype, :(jlread($io, ArrayDatatype))))
         elseif $datatype_class << 4 == DT_ENUMERATED << 4