Could not parse encoded and reserved charactor mixed path

[junkmb]

Hi,
I had a problem when parsing URL which mixture of UTF-8 encoded and reserved URI charactors.

Version

• dart: 2.5.0
• uri: 0.11.3+1

Example

username: サンプル@example.com

var uri = Uri.parse("https://example.com/users/サンプル@example.com");
print("uri: $uri");
// uri: https://example.com/users/%E3%82%B5%E3%83%B3%E3%83%97%E3%83%AB@example.com
// Encoded like this automatically

var template = UriTemplate("/users/{+username}");
var parser = UriParser(template);
var params = parser.parse(uri);
print("params: $params");
// ParseException: /users/{+username} does not match https://example.com/users/%E3%82%B5%E3%83%B3%E3%83%97%E3%83%AB@example.com
// expect: {username: %E3%82%B5%E3%83%B3%E3%83%97%E3%83%AB@example.com}

I think this caused by regexp in _Compiler._compilePath method does not include % character.
For this reason, template expansion/parsing with + operator seems to have no reversibility as below.

Additional: Example based on RFC6570 1.2. Level 2

var template = UriTemplate("/{+hello}");
var parser = UriParser(template);

var uri = parser.expand({"hello": "Hello World!"});
print("uri: $uri");
// uri: /Hello%20World!

var params = parser.parse(uri);
print("params: $params");
// params: {hello: Hello} <- expect: {hello: Hello%20World!}