don't escape non-ascii characters in docker env file

lib/kamal/env_file.rb

@@ -24,6 +24,13 @@ class Kamal::EnvFile
 
     # Escape a value to make it safe to dump in a docker file.
     def escape_docker_env_file_value(value)
+      # keep non-ascii(UTF-8) characters as it is
+      value.to_s.scan(/[\x00-\x7F]+|[^\x00-\x7F]+/).map do |part|
+        part.ascii_only? ? escape_docker_env_file_ascii_value(part) : part
+      end.join
+    end
+
+    def escape_docker_env_file_ascii_value(value)
       # Doublequotes are treated literally in docker env files
       # so remove leading and trailing ones and unescape any others
       value.to_s.dump[1..-2].gsub(/\\"/, "\"")

test/env_file_test.rb

@@ -11,6 +11,33 @@ class EnvFileTest < ActiveSupport::TestCase
       Kamal::EnvFile.new(env).to_s
   end
 
+  test "to_str won't escape chinese characters" do
+    env = {
+      "foo" => '你好 means hello, "欢迎" means welcome, that\'s simple! 😃 {smile}'
+    }
+
+    assert_equal "foo=你好 means hello, \"欢迎\" means welcome, that's simple! 😃 {smile}\n",
+      Kamal::EnvFile.new(env).to_s
+  end
+
+  test "to_s won't escape japanese characters" do
+    env = {
+      "foo" => 'こんにちは means hello, "ようこそ" means welcome, that\'s simple! 😃 {smile}'
+    }
+
+    assert_equal "foo=こんにちは means hello, \"ようこそ\" means welcome, that's simple! 😃 {smile}\n", \
+      Kamal::EnvFile.new(env).to_s
+  end
+
+  test "to_s won't escape korean characters" do
+    env = {
+      "foo" => '안녕하세요 means hello, "어서 오십시오" means welcome, that\'s simple! 😃 {smile}'
+    }
+
+    assert_equal "foo=안녕하세요 means hello, \"어서 오십시오\" means welcome, that's simple! 😃 {smile}\n", \
+      Kamal::EnvFile.new(env).to_s
+  end
+
   test "to_s empty" do
     assert_equal "\n", Kamal::EnvFile.new({}).to_s
   end

test/integration/docker/deployer/app/.env.erb

@@ -1 +1 @@
-SECRET_TOKEN=1234
+SECRET_TOKEN='1234 with "中文"'

test/integration/docker/deployer/app_with_roles/.env.erb

@@ -1 +1 @@
-SECRET_TOKEN=1234
+SECRET_TOKEN='1234 with "中文"'

test/integration/main_test.rb

@@ -3,8 +3,8 @@ require_relative "integration_test"
 class MainTest < IntegrationTest
   test "envify, deploy, redeploy, rollback, details and audit" do
     kamal :envify
-    assert_local_env_file "SECRET_TOKEN=1234"
-    assert_remote_env_file "SECRET_TOKEN=1234"
+    assert_local_env_file "SECRET_TOKEN='1234 with \"中文\"'"
+    assert_remote_env_file "SECRET_TOKEN=1234 with \"中文\""
     remove_local_env_file
 
     first_version = latest_app_version
@@ -16,7 +16,7 @@ class MainTest < IntegrationTest
     assert_hooks_ran "pre-connect", "pre-build", "pre-deploy", "post-deploy"
     assert_env :CLEAR_TOKEN, "4321", version: first_version
     assert_env :HOST_TOKEN, "abcd", version: first_version
-    assert_env :SECRET_TOKEN, "1234", version: first_version
+    assert_env :SECRET_TOKEN, "1234 with \"中文\"", version: first_version
 
     second_version = update_app_rev