RubyDNS is failing oddly with Ruby 2.7, so let's just skip it

spec/integration/reconnect_spec.rb

@@ -111,6 +111,8 @@
       # thread.kill should've similarly failed, but it doesn't.
       fails_on_jruby
 
+      minimum_mri_version '3.0.0'
+
       it 'recreates SRV monitor' do
         wait_for_discovery
 

spec/integration/srv_monitoring_spec.rb

@@ -76,6 +76,8 @@
     # NotImplementedError: recvmsg_nonblock is not implemented
     fails_on_jruby
 
+    minimum_mri_version '3.0.0'
+
     around do |example|
       # Speed up the tests by listening on the fake ports we are using.
       done = false

spec/support/constraints.rb

@@ -17,6 +17,16 @@ def require_local_tls
     end
   end
 
+  def minimum_mri_version(version)
+    require_mri
+
+    before(:all) do
+      if RUBY_VERSION < version
+        skip "Ruby #{version} or greater is required"
+      end
+    end
+  end
+
   def forbid_x509_auth
     before(:all) do
       skip 'X.509 auth not allowed' if SpecConfig.instance.x509_auth?