Phx.tools updates following Elixir 1.18 release

Following the recent release of Elixir 1.18 and subsequent 1.18.1, we’ve updated Phx.tools.

- Updated Elixir to version 1.18.1
- Updated Erlang to 27.2
- Updated Phoenix to 1.7.18

Check it out: https://phx.tools.