[ruby/openssl] test/openssl/test_ssl: relax regex to match OpenSSL's error message

OpenSSL 3.0 slightly changed the error message for a certificate
verification failure when an untrusted self-signed certificate is found
in the chain.

https://github.com/ruby/openssl/commit/b5a0a19850

test/openssl/test_ssl.rb

@@ -1023,7 +1023,9 @@ class OpenSSL::TestSSL < OpenSSL::SSLTestCase
     start_server(ignore_listener_error: true) { |port|
       ctx = OpenSSL::SSL::SSLContext.new
       ctx.set_params
-      assert_raise_with_message(OpenSSL::SSL::SSLError, /self signed/) {
+      # OpenSSL <= 1.1.0: "self signed certificate in certificate chain"
+      # OpenSSL >= 3.0.0: "self-signed certificate in certificate chain"
+      assert_raise_with_message(OpenSSL::SSL::SSLError, /self.signed/) {
         server_connect(port, ctx)
       }
     }