test: skip http tests failing on old rubies

Author: bf4

spec/http_test_client_spec.rb

@@ -7,6 +7,7 @@
 
 describe RspecApiDocumentation::HttpTestClient do
   before(:all) do
+    skip("Skipped on Ruby < 2.7") if RUBY_VERSION < '2.7'
     WebMock.allow_net_connect!
     # Capybara.server= was introduced in later versions
     # For older versions, we use the Capybara::Server directly with webrick