bump to Erlang 25?

[yosifkit]

The releases notes of both RabbitMQ server 3.10.7 and 3.9.22 say they support Erlang 25:

This release requires at least Erlang 24.x, and supports Erlang 25.

Though, it doesn't look like https://www.rabbitmq.com/which-erlang.html is updated quite yet. ❤️

I'm not certain when we should bump the erlang version. 😕 Perhaps we wait for the next minor bumps (like 3.10.8 and 3.9.23), or maybe only on the next major, (like 3.11.x). 🤔 We could also do it without waiting for a bump at all (assuming it is safe like previous previous erlang 24 bump: #486).

cc @michaelklishin should we move the images to erlang 25? Maybe just the 3.10 images?

[michaelklishin]

Just the 3.10 ones for now. 3.9.x does run on Erlang 25 but we don't promote that fact since Erlang 25 support is a "feature", too.

[michaelklishin]

Towards the end of its lifecycle next spring, Erlang 24 will be close to its EOL, then moving 3.9 to 25, even if for a month or two, would make sense.