Keep XLIFF attributes

[Lumbendil]

It'd be nice that this bundle, when regenerating an XLIFF file, it kept the attributes.

<trans-unit id="b95d03a2faceaf98932af3c912c19df68bdb2084" resname="Clave" approved="yes">
    <jms:reference-file line="26">Form/Type/UserEditType.php</jms:reference-file>
    <jms:reference-file line="26">Form/Type/UserRegisterType.php</jms:reference-file>
    <source>Clave</source>
    <target state="translated">Senha</target>
</trans-unit>

In this example, the state of translated and the approved are lost when regenerating the file.

[nixilla]

+1

[GabLeRoux]

I've been using this PR and I confirm it does keep approved="yes", Been using this within weblate and it works. I couldn't find a way to display resname in weblate sidebar thought. Thanks for this (This bundle really doesn't seem to be maintained anymore)

[Nyholm]

Closed by #356