dpkg 1.22.6ubuntu11 enables ELF packaging metadata

[Benjamin Drung]

Hi everyone,

I just uploaded dpkg 1.22.6ubuntu11 to Ubuntu oracular. This version
enables ELF packaging metadata via dpkg-buildflags by default. ELF
objects will record the spec https://systemd.io/ELF_PACKAGE_METADATA/
Example data:

```
$ readelf --notes/usr/bin/leak-memory | grep Metadata
    Packaging Metadata: {"type":"deb","os":"ubuntu","osVersion":"24.10","name":"chaos-marmosets","version":"0.2.0-1","architecture":"amd64"}
```

This features is enabled by default. To opt out set:
DEB_BUILD_MAINT_OPTIONS = qa=-elfpackagemetadata

Thanks to Luca Boccassi for implementing it.

-- 
Benjamin Drung
Debian & Ubuntu Developer