Actually pass ssh/config through to SSHKit options

This option is documented as available since basecamp#908 in:
https://github.com/basecamp/kamal/blob/74a06b0ccda616c86ebe1729d0795f39bcac9f00/lib/kamal/configuration/docs/ssh.yml#L65-L70

However, before this the options don't seem to pass through to SSHKit:
https://github.com/basecamp/kamal/blob/74a06b0ccda616c86ebe1729d0795f39bcac9f00/lib/kamal/commander.rb#L167

Since `config` isn't actually returned in `#options`.

lib/kamal/configuration/ssh.rb

@@ -38,8 +38,12 @@ def key_data
     ssh_config["key_data"]
   end
 
+  def config
+    ssh_config["config"]
+  end
+
   def options
-    { user: user, port: port, proxy: proxy, logger: logger, keepalive: true, keepalive_interval: 30, keys_only: keys_only, keys: keys, key_data: key_data }.compact
+    { user: user, port: port, proxy: proxy, logger: logger, keepalive: true, keepalive_interval: 30, keys_only: keys_only, keys: keys, key_data: key_data, config: config }.compact
   end
 
   def to_h

test/configuration/ssh_test.rb

@@ -37,4 +37,9 @@ class ConfigurationSshTest < ActiveSupport::TestCase
     config = Kamal::Configuration.new(@deploy.tap { |c| c.merge!(ssh: { "proxy" => "[email protected]" }) })
     assert_equal "[email protected]", config.ssh.options[:proxy].jump_proxies
   end
+
+  test "ssh options with disabled ssh_config" do
+    config = Kamal::Configuration.new(@deploy.tap { |c| c.merge!(ssh: { "config" => false }) })
+    assert_equal false, config.ssh.options[:config]
+  end
 end