Changelog:
==============
- support for loading dataclasses with 'InitVar' variables (some
special coding was necessary to get the, unexecpected, default
value in the corresponding instance attribute
in [this question](https://stackoverflow.com/q/
77228378/
1307905))
- Python 3.12 also loads C version when using 'typ='safe''
- added 'flow_seq_start', 'flow_seq_end',
'flow_seq_separator', 'flow_map_start',
'flow_map_end', 'flow_map_separator'
**class** attributes to the 'Emitter' class so flow
style output can more easily be influenced
Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>