Fix Java 25 ftbfs
This MR resolves 1108556.
pom.xml sets source/target properties instead of release. This change sets compiler release forcing API compatibility with Java 11. Upstream uses release property: https://github.com/BaseXdb/basex/blob/1a582b66a836fb0aae5766ed367e3910d96b77d9/pom.xml#L17 This change should be rolled back when updating to the latest upstream.
Testing:
- rebuild in sid chroot
- rebuild in sid chroot with Java 25 default.