Bug fixes:
* Fixed incorrect handling of models with end times > 0 in a demes Graph.
When exporting to tskit, alive node times were treated as 0.0, causing
potential problems for some use cases.
Issue {issue}`1253`
PR {issue}`1255`
Deprecations
* Deprecate the `demes_graph` argument to {func}`fwdpy11.DiploidPopulation.dump_tables_to_tskit`
PR {issue}`1265`
* Deprecate using a dict for the the `model_params` argument to {func}`fwdpy11.DiploidPopulation.dump_tables_to_tskit`
PR {issue}`1265`