Preparing CRAN submission

[gvegayon]

This pull request includes several changes to the epiworldR package, focusing on updates to versioning, documentation, and model parameters. The most important changes include updating the versioning system, modifying README examples, and updating the citation information.

Versioning and Documentation Updates:

• DESCRIPTION: Updated the package version to 0.6.0.0 and adjusted author roles.
• NEWS.md: Changed the version number and added a note about the new versioning system for R-only patches. [1] [2]

README Example Updates:

• README.md: Updated SIR model final distribution and performance metrics. [1] [2] [3]
• README.md: Adjusted agent states and reproductive number values in the model examples. [1] [2]

Citation Information:

• README.md: Updated the citation information to reflect the new version and authorship.
• inst/CITATION: Updated the citation year to 2024 and added Andrew Pulsipher as an author. [1] [2]

Vignette Updates:

• vignettes/likelihood-free-mcmc.Rmd: Modified model parameters and added a new section to plot parameter traces. [1] [2] [3] [4] [5]

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 38.72%. Comparing base (43399ea) to head (b3af658).
Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   38.72%   38.72%           
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  Files          36       36           
  Lines        2058     2058           
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  Hits          797      797           
  Misses       1261     1261           

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