use Lognormal.from_mean_std in RiskyAsset forward simulation

[sbenthall]

fixes #1003

• [x ] Updated documentation of features that add new functionality.
• Update CHANGELOG.md with major/minor changes.

[codecov-commenter]

Codecov Report

Merging #1019 (4a509fb) into master (085ea3a) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

❗ Current head 4a509fb differs from pull request most recent head abc02f2. Consider uploading reports for the commit abc02f2 to get more accurate results

@@            Coverage Diff             @@
##           master    #1019      +/-   ##
==========================================
- Coverage   72.43%   72.42%   -0.02%     
==========================================
  Files          66       66              
  Lines        9871     9867       -4     
==========================================
- Hits         7150     7146       -4     
  Misses       2721     2721              

Impacted Files	Coverage Δ
HARK/distribution.py	80.60% <ø> (ø)
HARK/ConsumptionSaving/ConsRiskyAssetModel.py	85.93% <100.00%> (-0.83%)	⬇️

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[Mv77]

Looks great to me