Fix CI builds

[codealchemy]

There has been a Typhoeus spec that has been failing in this project for a few months (most recently in #962), it seems to be tied to the 0.16.0 release of the ethon gem (typhoeus/ethon@v0.15.0...v0.16.0)

Failure

  1) Typhoeus hook when using on_headers callback is expected to yield with args(have attributes {:headers => (include {"Content-Length" => "18"})})
     Failure/Error: it { expect { |b| on_headers(&b) }.to yield_with_args(have_attributes(headers: include('Content-Length' => '18'))) }

       expected given block to yield with arguments, but yielded with unexpected arguments
       expected: [(have attributes {:headers => (include {"Content-Length" => "18"})})]
            got: [#<Typhoeus::Response:0x00007f66226d9ae0 @options={:httpauth_avail=>0, :total_time=>8.2e-05, :starttr...s=>"", :response_body=>"", :debug_info=>#<Ethon::Easy::DebugInfo:0x00007f66226e4a58 @messages=[]>}>]
     # ./spec/lib/vcr/library_hooks/typhoeus_spec.rb:124:in `block (3 levels) in <top (required)>'