Create a PG13 version #5
Description
The current Dockerfile is for PG12, and a one-character change produces a working version for PG11. That doesn't work for PG13 however. We should create a PG13 version of our container that can be pushed to a latest-pg13 tag.
We'll need to understand how Timescale Cloud differs between the two. Do available extensions or versions differ? Do they use pgextwlist or PG13's native extension whitelisting?