Migrate to Faraday 2.x

[Watson1978]

This PR upgrades the faraday dependency from 1.x to 2.x and resolves several breaking changes.

Currently, this library is running the test suite fails with a NameError because the older typhoeus gem attempts to modify Faraday's internal adapter classes using a legacy structure that is no longer compatible with Faraday 2.x.

$ bundle exec rake test
/home/watson/.rbenv/versions/3.4.8/bin/ruby -w -I"lib:test" /home/watson/.rbenv/versions/3.4.8/lib/ruby/gems/3.4.0/gems/rake-13.3.1/lib/rake/rake_test_loader.rb "test/test_client.rb"
/home/watson/.rbenv/versions/3.4.8/lib/ruby/gems/3.4.0/gems/typhoeus-1.1.2/lib/typhoeus/adapters/faraday.rb:28:in 'Module#remove_method': method 'call' not defined in Faraday::Adapter::Typhoeus (NameError)

      remove_method :call              if method_defined? :call
      ^^^^^^^^^^^^^
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/gems/3.4.0/gems/typhoeus-1.1.2/lib/typhoeus/adapters/faraday.rb:28:in '<class:Typhoeus>'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/gems/3.4.0/gems/typhoeus-1.1.2/lib/typhoeus/adapters/faraday.rb:21:in '<class:Adapter>'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/gems/3.4.0/gems/typhoeus-1.1.2/lib/typhoeus/adapters/faraday.rb:4:in '<module:Faraday>'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/gems/3.4.0/gems/typhoeus-1.1.2/lib/typhoeus/adapters/faraday.rb:3:in '<top (required)>'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/3.4.0/bundled_gems.rb:82:in 'Kernel.require'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/3.4.0/bundled_gems.rb:82:in 'block (2 levels) in Kernel#replace_require'
        from /home/watson/src/ruby-zulip-client/lib/zulip/client.rb:5:in '<top (required)>'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/3.4.0/bundled_gems.rb:82:in 'Kernel.require'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/3.4.0/bundled_gems.rb:82:in 'block (2 levels) in Kernel#replace_require'
        from /home/watson/src/ruby-zulip-client/test/helper.rb:4:in '<top (required)>'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/3.4.0/bundled_gems.rb:82:in 'Kernel.require'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/3.4.0/bundled_gems.rb:82:in 'block (2 levels) in Kernel#replace_require'
        from /home/watson/src/ruby-zulip-client/test/test_client.rb:1:in '<top (required)>'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/3.4.0/bundled_gems.rb:82:in 'Kernel.require'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/3.4.0/bundled_gems.rb:82:in 'block (2 levels) in Kernel#replace_require'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/gems/3.4.0/gems/rake-13.3.1/lib/rake/rake_test_loader.rb:21:in 'block in <main>'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/gems/3.4.0/gems/rake-13.3.1/lib/rake/rake_test_loader.rb:6:in 'Array#select'
        from /home/watson/.rbenv/versions/3.4.8/lib/ruby/gems/3.4.0/gems/rake-13.3.1/lib/rake/rake_test_loader.rb:6:in '<main>'
rake aborted!

This PR will migrate to 2.x to resolve the above error.

Fix #6

[Watson1978]

Thanks