Broken on ruby 2.7

[zenspider]

I've put in a PR (#860) to fix up a lot of the deprecation warnings but I haven't the time or understanding to dig into the actual failures. Looks like CI has been red for a while tho.

ETA: 2.7 comes out in mere weeks...

[kzkn]

One of reason: https://github.com/httprb/http/issues/582 This causes some errors like below:

  1) HTTP.rb with WebMock allows a response with multiple values for the same header to be recorded and played back exactly as-is
     Failure/Error: webmock_response.body    = body.to_s
     
     FrozenError:
       can't modify frozen String: ""
     Shared Example Group: "complex cross-concern behaviors" called from ./spec/acceptance/webmock_shared.rb:39
     Shared Example Group: "with WebMock" called from ./spec/acceptance/http_rb/http_rb_spec.rb:10
     # /home/travis/.rvm/gems/ruby-2.7.0/gems/http-4.2.0/lib/http/response/body.rb:52:in `force_encoding'
(snip)

[ixti]

We just released http-4.3.0 that brings ruby-2.7 support.

[kzkn]

Broken specs have fixed. https://travis-ci.org/bblimke/webmock/jobs/634932029