Add sensitivity analysis to README

All of the relevant input data and plotting scripts were added in previous commits. This commit adds this analysis to the top-level list of what analyses we performed as part of this project.

README.md

@@ -52,3 +52,4 @@ Below are brief descriptions of the analyses we conducted for this project, with
 * [Maximum likelihood analysis of HIV-Protease and HIV-RT sequences](HIV/max_likelihood/)
 * [Temporally-resolved phylogenetic trees estimated for HCV](HCV/bayesian_timetree/)
 * [Temporally-resolved phylogenetic trees estimated for HIV-Env](HIV/bayesian_timetree)
+* [Sensitivity analysis to look at clock prior choice affects population dynamics and the inferred epidemic growth rate](HIV/bayesian_skyline/)