Remove the dependency on std.xml

[shoo]

In D 2.092.0, std.xml is marked as deprecated.
Since the dub uses std.xml, we need to remove this dependency.

There is only one place that depends on std.xml, which is as follows:

dub/source/dub/packagesuppliers/maven.d

Line 82 in c1ee378

import std.xml;

[rikkimax]

deprecated("Will be removed from Phobos in 2.101.0. If you still need it, go to https://github.com/DigitalMars/undeaD")

[andre2007]

What would be a good solution? My first idea would be to copy the code of std.xml undead to source/dub/internal folder.

[rikkimax]

What would be a good solution? My first idea would be to copy the code of std.xml undead to source/dub/internal folder.

Add it as a dependency until somebody bothers with a rewrite. That is the simplest answer.

[andre2007]

The xml parsing is replaced with std.regex:
#1977