faraday-retry missing from gemspec dependencies

[n-at-han-k]

Please see the comment below from a previous issue.
The faraday-retry gem is missing from the gemspec.
Simply installing telnyx makes rails apps unbootable.
Running bundle add faraday-retry fixes this.

          @ADandyGuyInSpace I was setting up this gem in a new project and ran into a load error with this gem requiring `faraday/retry`. I believe `faraday-retry` needs to be added to as a dependency in `telnyx.gemspec`. Adding it to my own `Gemfile` resolved my load issue.

/usr/local/lib/ruby/3.3.0/bundled_gems.rb:75:in `require': cannot load such file -- faraday/retry (LoadError)
	from /usr/local/lib/ruby/3.3.0/bundled_gems.rb:75:in `block (2 levels) in replace_require'
	from /usr/local/bundle/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:17:in `require'
	from /usr/local/bundle/gems/telnyx-3.0.3/lib/telnyx.rb:7:in `<main>'

Originally posted by @daneshd in #83 (comment)