graphics/plantuml: Update 1.2026.1 => 1.2026.5, take maintainership
Changelogs:
https://github.com/plantuml/plantuml/releases/tag/v1.2026.2
https://github.com/plantuml/plantuml/releases/tag/v1.2026.3
https://github.com/plantuml/plantuml/releases/tag/v1.2026.4
https://github.com/plantuml/plantuml/releases/tag/v1.2026.5
PR: 295670
Approved by: awoonya <awoonyaa@gmail.com> (maintainer, inactive for over 2 years with multiple timeouts)
Sponsored by: UNIS Labs
MFH: 2026Q2