Use postgres 14

[lognaturel]

Match what the standard setup will be starting with 2023.2. There are no changes needed to the code so we might as well start doing this now.

What has been done to verify that this works as intended?

Nothing, CI should be enough.

Why is this the best possible solution? Were any other approaches considered?

We could wait until we're ready to release backend but I don't see any advantage in that. I used 14.6 which is the latest available from CircleCI. This matches our recommendations in docs.

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

None, this is CI only.

Does this change require updates to the API documentation? If so, please update docs/api.md as part of this PR.

No.

Before submitting this PR, please make sure you have:

• run make test-full and confirmed all checks still pass OR confirm CircleCI build passes
• verified that any code from external sources are properly credited in comments

[matthew-white]

I searched the codebase for "9.6" and see a few other references:

• .github/workflows/soak-test.yml
• run-docker-postgres in the makefile. @ktuite, I know you use run-docker-postgres in development. How easy do you think it would be to change the version of Postgres there?
• We link to the Postgres 9.6 docs from the API docs in one place.

[ktuite]

Good catches, @matthew-white!

I updated the postgres docker image for the soak test:

• .github/workflows/soak-test.yml

Following the convention in the overall postgres update of calling the new docker container postgres14 instead of just postgres, I renamed the container made by this command. This lets me keep my old container around and figure out how to copy over data later or just deal with having a fresh dev database.

• run-docker-postgres in the makefile. @ktuite, I know you use run-docker-postgres in development. How easy do you think it would be to change the version of Postgres there?

Updated this link

• We link to the Postgres 9.6 docs from the API docs in one place.