Hi Chris,
Using your site locally, I cannot get your bibliography to show up for that post either. But, in a new post citing R packages (I copied from this blog post: https://raw.githubusercontent.com/rbind/blogdown-demo/master/content/post/2017-08-28-adding-citations-to-posts.Rmd), I was able to get them to show up.
I went back to your repo and realized you are using .Rmarkdown posts instead of .Rmd. Interestingly, that matters!
Here is my repo:
and the rendered site:
https://chriscastille.netlify.com/