Make a release of jupyter-rsession-proxy

[yuvipanda]

jupyterhub/jupyter-rsession-proxy#159 (and to an extent jupyterhub/jupyter-rsession-proxy#160) add significantly useful functionality, and we should make a release of jupyter-rsession-proxy!

Definition of Done

• Test with slightly older and latest rstudio version
• Make a release
• Write up experience of making that release in Round 1: Strategic upstream OSS contributions #5058

[GeorgianaElena]

Assigning @sgibson91 to perform the actual release and I will be available in case something comes up

[yuvipanda]

If you want a dockerfile for testing, jupyterhub/jupyter-rsession-proxy#159 (comment) was the example I used.