Unable to start, start.boot missing

Trying to run expert lsp with neovim I get the following error in the lsp.log:

```
Engine build failed for my_app::7759237
Build script exited with status: 1
Crash dump is being written to: erl_crash.dump...done
```

One of the first lines of the `erl_crash.dump` says:

```
Slogan: Runtime terminating during boot ({'cannot get bootfile','/home/linuxbrew/.linuxbrew/Cellar/expert/0.1.2/libexec/expert/bin/start.boot'})
```

And surely, that file does not expert.

I've installed expert using homebrew under WSL2. Mise is used to manage Erlang/Elixir if that makes a difference.

I've tried copying `start.boot` from `/home/linuxbrew/.linuxbrew/Cellar/expert/0.1.2/libexec/expert/releases/0.1.2/start.boot` which leads to the error:
```
Slogan: Runtime terminating during boot ('cannot expand $RELEASE_LIB in bootfile')
```

Neovim version 0.12.2
Expert 0.1.2