Pass rng in evolve_states

[actapia]

This change makes the evolve_states method of DiscreteCharacterEvolver pass its rng parameter to seq_model.simulate_descendant_states.

Before the change, this code results in an AssertionError:

from random import Random
from dendropy.model import discrete
from dendropy.simulate import treesim

def test_chars(t, rng):
    return sorted(str(s) for s in discrete.hky85_chars(10, t, rng=rng).values())

if __name__ == "__main__":
    tree = treesim.birth_death_tree(
        birth_rate=1.0,
        death_rate=0.5,
        num_extant_tips=4,
        rng=Random(100)
    )
    t1 = test_chars(tree, Random(100))
    t2 = test_chars(tree, Random(100))
    assert t1 == t2

After this change, the assertion succeeds.

[mmore500]

Good catch! Activated CI for this branch so we can test the change. Planning to add a regression test for this issue shortly to our unit test suite for this bug then merge and push a new release. Thanks for the PR!

[codecov-commenter]

Codecov Report

Merging #170 (c57b7c5) into main (877a172) will increase coverage by 0.66%. The diff coverage is 100.00%.

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@@            Coverage Diff             @@
##             main     #170      +/-   ##
==========================================
+ Coverage   60.75%   61.42%   +0.66%     
==========================================
  Files         105      105              
  Lines       18646    18646              
==========================================
+ Hits        11329    11453     +124     
+ Misses       7317     7193     -124     

Flag	Coverage Δ
unittests	61.42% <100.00%> (+0.66%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/dendropy/model/discrete.py	76.43% <100.00%> (+56.54%)	:arrow_up:

... and 3 files with indirect coverage changes

[mmore500]

Found another place where rng wasn't being passed!

[mmore500]

A patch has been released as v.4.6.1

Thank you again for the contribution.