Allow serializing of patch resolves items for xml

[schlenk]

Add the necessary parts to serialize the resolves part of patches to XML.

fixes #313

[jkowalleck]

could you add tests?

[schlenk]

I'll give it a try.

[jkowalleck]

please be aware that there is currently a feature stop while v4 is in the making.
see https://github.com/CycloneDX/cyclonedx-python-lib/milestone/4
see #262

this means your feature might not be merged before v4 was drafted.
⚡ I would advice you to open an issue describing the feature you try to implement.
we then can discuss how the implementation process can be done in a coordinated way.

[schlenk]

That is okay.
The patch will actually become smaller, as the serialization for issues is already there (just inside the release_notes, not for patches), noticed it while trying to write a test. So its basically is just a bit of code reuse.

[jkowalleck]

any updates?
is this still relevvant?

[schlenk]

This seems to be fixed and obsolete with the new serialization since 4.0.