UTF-8 issues on Windows 10

[xconverge]

This is related to #2, I think his fix will most likely work, I also followed this issue on the other popular copy paste library.

Run the following test:

test.only('works with unicode', async t => {
const f = '你好';
t.is(await writeRead(f), f);
});

Now open any other program, notepad etc, and do Edit-Copy or Ctrl+V and you will get 你好.

This is going to be difficult to write a test for since from the libraries standpoint, everything is good. Outside of the library however, it is not actually working with the correct clipboard contents due to encoding.

[xconverge]

@sindresorhus @notatestuser any thoughts here?