Bump library/ruby from 3.4.8-slim to 4.0.0-slim

Bumps library/ruby from 3.4.8-slim to 4.0.0-slim.

---
updated-dependencies:
- dependency-name: library/ruby
  dependency-version: 4.0.0-slim
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Dockerfile

@@ -8,7 +8,7 @@
 # For a containerized dev environment, see Dev Containers: https://guides.rubyonrails.org/getting_started_with_devcontainer.html
 
 # Make sure RUBY_VERSION matches the Ruby version in .ruby-version
-FROM registry.docker.com/library/ruby:3.4.8-slim@sha256:ab799da9ea11230e3e28f0b60de30f801e036624affbcbff1d206088d89b730d AS base
+FROM registry.docker.com/library/ruby:4.0.0-slim@sha256:af10ee4286a55db1d975744717991c61a5c7d5b02b43bdf61386213f3cba789b AS base
 
 LABEL maintainer="Ihor Zubkov <igor.zubkov@gmail.com>"