Maintenance release integrating new tskit features

[1.1.0] - 2021-12-14

New features

• Add support for tree sequence time_units field. The time_units will be set to “generations” for the output of sim_ancestry (and simulate), unless the initial_state argument is used. In this case, the time_units value will be inherited from the input. (#1953, #1951, #1877, #1948, @jeromekelleher).

Bug fixes:

• Raise an error if Demography.from_demes() is passed a model with non-zero selfing_rate or cloning_rate values (which msprime does not support). (#1938, #1937, @grahamgower).

• Do not assume Population metadata schemas contain the properties and additionalProperties attributes (#1947, #1954, @jeromekelleher).

• Read the population name from PopulationConfiguration metadata in Demography.from_old_style (#1950, #1954, @jeromekelleher)

Maintenance:

• Update tskit to Python 0.4.0 and C 0.99.15.