feat: Use tini as entrypoint

[reneleonhardt]

Updates

• Alpine 3.20 (fixes 5 security findings)
• Let Dependabot update images in Dockerfile, docker-compose.yml and Kubernetes manifests

Improvements

• Use tini as entrypoint for Dockerfile and docker-compose.yml example

Transfer size (compressed image) should be

• amd64 = 7.1 MB
• arm64 = 7.6 MB
• multi = 14.7 MB

[jflambert]

Do you have more info about Dependabot

[reneleonhardt]

Microsoft offers free usage for Open-Source projects, it automatically creates PRs when it sees updates:
https://docs.github.com/en/code-security/getting-started/dependabot-quickstart-guide
https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file

My example configuration searches for updates of Docker image tags in Dockerfile, docker-compose.yml and Kubernetes manifests.
After you pushed a new pgbouncer image, Dependabot will offer you a PR if you didn't already change all 1.9.0 tags in this repo for example.
Or postgres:17-alpine after it has been released in September 😅

[jflambert]

I've used tini in other projects where, as you say, I needed to handle some signals gracefully or other esoteric things (subreaping, capture some non-standard output). Which problems does this solve for pgbouncer?

[jflambert]

is the --repository switch necessary if we're already using alpine 3.20?

feels like tini could be added to line 8 instead