This PR adds the r-dss package and the r-bsseq package, also new, as a
dependency. This includes the latest versions, which required updates to
the following dependencies:

- r-biocgenerics
- r-iranges
- r-s4vectors
- r-summarizedexperiment

Older versions of r-dss and r-bsseq are included as well to ensure
compatibility with older versions of the above dependencies.