Outdated test samples

[MAKOMO]

Most of the test files in tests/samples are ZUGFeRD 2.1.1 (July 1, 2020) using still the outdated namespace

xmlns:qdt="urn:un:unece:uncefact:data:standard:QualifiedDataType:10"

for qualified data types instead of

xmlns:qdt="urn:un:unece:uncefact:data:standard:QualifiedDataType:10"

as of the current ZUGFeRD 2.2.