Fix failing tests on Ruby 3.4 because of hash inspect changes

[Earlopain]

Ruby has changed the output of Hash.inspect, causing some test failures.

Instead of hardcoding it, just call inspect itself to pass tests on old and new rubies

Ref:

• Hash#inspect with colon style ruby/ruby#10924
• https://bugs.ruby-lang.org/issues/20433

Note that I still have some failing tests like this:

1) Excon with WebMock when after_request callback is declared should invoke callbacks only for real requests if requested
     Failure/Error: response = Excon.new(uri, excon_options.merge(nonblock: false)).request(options, &block)
     
     Excon::Error::Socket:
       undefined method 'casecmp' for nil (NoMethodError)
     Shared Example Group: "callbacks" called from ./spec/acceptance/webmock_shared.rb:43
     Shared Example Group: "with WebMock" called from ./spec/acceptance/excon/excon_spec.rb:7
     # ./spec/acceptance/excon/excon_spec_helper.rb:22:in 'ExconSpecHelper#http_request'
     # ./spec/acceptance/shared/callbacks.rb:136:in 'block (3 levels) in <top (required)>'
     # ./spec/acceptance/webmock_shared.rb:26:in 'block (3 levels) in <top (required)>'
     # ./lib/webmock/rspec.rb:39:in 'block (2 levels) in <top (required)>'
     # ------------------
     # --- Caused by: ---
     # NoMethodError:
     #   undefined method 'casecmp' for nil
     #   ./spec/acceptance/excon/excon_spec_helper.rb:22:in 'ExconSpecHelper#http_request'

Finished in 0.67789 seconds (files took 0.81427 seconds to load)
1 example, 1 failure

Failed examples:

rspec ./spec/acceptance/excon/excon_spec.rb[1:1:10:9] # Excon with WebMock when after_request callback is declared should invoke callbacks only for real requests if requested

I have not looked into those yet. I did notice that excon very recently released 1.0.0, maybe it's related to that.

[Earlopain]

Created an upstream issue for excon excon/excon#862 / excon/excon#863

[Earlopain]

Can someone with a bit more knowledge chime in at excon/excon#863? I'm not qualified for that and it's a bit more complicated than I thought