Drop Priority: optional, which is the default in Trixie

[elboulangero]

When omitted, the priority defaults to optional (since dpkg 1.22.13).

Cf. man deb-src-control.

[elboulangero]

Let's hold on a bit for this one. I tried, and noticed that Lintian complains:

Running lintian...
W: golang-github-oschwald-maxminddb-golang-v2 source: recommended-field (in section for source) Priority [debian/control:1]

$ lintian-explain-tags recommended-field
N:
W: recommended-field
N: 
N:   The named field is recommended by policy but not present in the package's primary control file.
N: 
N:   Please refer to Source package control files – debian/control (Section 5.2) in the Debian Policy Manual, Binary package control files – DEBIAN/control (Section 5.3) in the Debian Policy Manual, and Debian changes files – .changes (Section
N:   5.5) in the Debian Policy Manual for details.
N: 
N:   Visibility: warning
N:   Show-Always: no
N:   Check: fields/recommended
N:   Renamed from: no-priority-field no-section-field-for-source no-section-field no-urgency-in-changes-file
N: 

Indeed, the Debian policy was not yet updated to reflect this change: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1110017