v.2.0.1.3

Forgot to create a release for 2.0.1, so this is it plus some additional changes based on the rOpenSci review which will be incorporated into the CRAN version 2.0.2 later. From the NEWS:

bssm 2.0.1.3

• Switched to markdown NEWS with a plan to be more clear about the future
  changes in the package.
• Added more details to the ?bssm help page.
• Added more details to the ?bssm_prior help page.
• Added option to extract only hyperparameters in as_draws method. Also
  fixed a but in as_draws which caused the it to ignore states argument.
• Added a default plot method for the run_mcmc output.

bssm 2.0.1 (Release date: 2022-05-02)

• Fixed weights to one in case of non-linear model with mcmc_type="approx".
• Adjusted tolerance of some testthat tests to comply with CRAN's MKL checks.