Time to add a 4.1.x version of the image :)

[michaelklishin]

Now that RabbitMQ 4.1.0-beta.1 is out, I think it would be a good moment to add a 4.1.x version of this image :)

Which can use Erlang 27 from the start #734.

Thank you!

[michaelklishin]

@tianon @yosifkit 4.1.0-beta.1 is produced using new build infrastructure that's publicly available.

One change that might affect this image is this: instead of two generic binary (UNIX) packages, one built on the oldest supported Erlang version and another built on "latest toolchain",
all packages are now produced on the latest Erlang 26.x and Elixir (currently 1.17.x).

So the -latest-toolchain version of the package is no longer available. I will likely add it back just as a copy of the currently produced artifact but ideally this image should use packaged named rabbitmq-server-generic-unix-{version}.tar.xz.