Eval proxy options

To ensure that the proxy options are evaluated as if they were
added verbatim to the command, we'll eval the docker run command.

Fixes: https://github.com/basecamp/kamal/issues/1448

test/integration/proxy_test.rb

@@ -46,7 +46,27 @@ class ProxyTest < IntegrationTest
     logs = kamal :proxy, :logs, capture: true
     assert_match /No previous state to restore/, logs
 
+    kamal :proxy, :boot_config, :set, "--docker-options='sysctl net.ipv4.ip_local_port_range=\"10000 60999\"'"
+        assert_docker_options_in_file
+
+    kamal :proxy, :reboot, "-y"
+    assert_docker_options_in_container
+    
+    kamal :proxy, :boot_config, :reset
+
     kamal :proxy, :remove
     assert_proxy_not_running
   end
+
+  private
+    def assert_docker_options_in_file
+      boot_config = kamal :proxy, :boot_config, :get, capture: true
+      assert_match "Host vm1: --publish 80:80 --publish 443:443 --log-opt max-size=10m --sysctl net.ipv4.ip_local_port_range=\"10000 60999\"", boot_config
+    end
+
+    def assert_docker_options_in_container
+      assert_equal \
+        "{\"net.ipv4.ip_local_port_range\":\"10000 60999\"}", 
+        docker_compose("exec vm1 docker inspect --format '{{ json .HostConfig.Sysctls }}' kamal-proxy", capture: true).strip
+    end
 end