Build Ruby 4.0.4

[rus-max]

https://www.ruby-lang.org/en/news/2026/05/11/ruby-4-0-4-released/
fullstaq-ruby/server-edition#193

[Envek]

4.0.4 packages are not available in the repository:

$ docker build --rm --pull --tag fullstaq-ruby:4.0.4-jemalloc-trixie-slim --build-arg RUBY_VERSION=4.0.4 --build-arg RUBY_VARIANT=jemalloc --build-arg DEBIAN_IMAGE=trixie-slim --build-arg DEBIAN_VERSION=13 .
…
8.927 Get:4 https://storage.googleapis.com/fsruby-server-edition-apt-repo/versions/49/public debian-13 InRelease [4322 B]
9.203 Get:5 https://storage.googleapis.com/fsruby-server-edition-apt-repo/versions/49/public debian-13/main amd64 Packages [10.9 kB]
9.234 Fetched 15.3 kB in 2s (7418 B/s)
9.234 Reading package lists...
9.627 Reading package lists...
10.00 Building dependency tree...
10.09 Reading state information...
10.14 E: Unable to locate package fullstaq-ruby-4.0.4-jemalloc
10.14 E: Couldn't find any package by glob 'fullstaq-ruby-4.0.4-jemalloc'
10.14 E: Couldn't find any package by regex 'fullstaq-ruby-4.0.4-jemalloc'

Hopefully this pull request will be replaced by #57 after its upstream pull request will be merged by maintainers. Closing.