Cast the timeout when fetching from JetStream

[jmdeldin]

We control our timeout via environment variables (worse – YAML) and had a silly bug in our code where the timeout was sent as a string. We kept running out of memory because the expires line was copying our string ("5") one billion times. D'oh!

This is just a simple fix to save new users like us some hassle.

I did run the js_spec.rb with this change, but I wasn't sure the preferred way (if any) of adding a test like this.

For others, this is what I did for a local Docker development setup:

# I added the base64 gem to the gemspec. I'm using Ruby 3.4-rc because concurrent ruby segfaults in 3.3.0.
% docker run -it -v $(pwd):/opt/app ruby:3.4-rc bash 
% bash ./scripts/install_nats.sh
% export PATH=$HOME/nats-server:$PATH
% nats-server &
% bundle install
% bundle exec rspec spec/js_spec.rb

[wallyqs]

LGTM