Symfony version(s) affected: 3.4

Description
When I dump string containing DEL(\x7f), Yaml::dump output string which contains DEL.

According to YAML specification,
DEL should not be included in YAML stream.
Some implementations throw error when trying to parse YAML stream containing DEL
(e.g. js-yaml and go-yaml)

How to reproduce

use Symfony\Component\Yaml\Yaml;

file_put_contents('test.yml', Yaml::dump(["DEL->\x7f<-here"]));

test.yml contains DEL character, and thus cannot be parsed by some implementation(eg. js-yaml)

Possible Solution
DEL(\x7f) should be escaped