fix(ci): remove dead reference to metanorma-build-scripts/plantuml-setup-action

[opoudjis]

Summary

Removes a dead reference to metanorma/metanorma-build-scripts/plantuml-setup-action@main from the shared make.yml reusable workflow. The action was deleted upstream 11 months ago; the reference has been silently failing on every PR run in every consumer repo since.

Failing runs (observed 2026-08-10)

• relaton/relaton-models PR fix(data-deploy): build relaton-cli from git by default, not the gem #66: run 31377259435
• relaton/relaton-model-ieee PR New repos in relaton found #10: run 31377306353

Both fail identically:

##[error] Can't find 'action.yml', 'action.yaml' or 'Dockerfile' for action
'metanorma/metanorma-build-scripts/plantuml-setup-action@main'.

Upstream removal

Commit metanorma/metanorma-build-scripts@1c8696e5, 2025-09-04, "Remove PlantUML installs and related actions". The removal was deliberate and provided no replacement.

Blast radius (all fixed by this one PR)

Seven repos delegate to this reusable via uses: relaton/support/.github/workflows/make.yml@main:

• relaton/relaton-models
• relaton/relaton-model-ieee
• relaton/relaton-model-3gpp
• relaton/relaton-model-ccsds
• relaton/relaton-model-oasis
• relaton/relaton-model-plateau
• relaton/relaton-model-w3c

Because all pin @main, merging this fixes them all instantly on their next PR run — no per-repo cascade needed.

Safety analysis — step deletion is safe, no replacement needed

• The affected repos' Makefiles do not reference PlantUML. Verified: grepped Makefile in relaton/relaton-models and relaton/relaton-model-ieee for plantuml|\.puml → zero hits. The bundle exec make clean all target doesn't invoke PlantUML.
• Scheduled runs on relaton/relaton-models@main have been green through 2026-08-07, empirically confirming the removal broke nothing real. Only the dead-reference resolution itself is what fails; the workflow never even attempts to run PlantUML.
• Upstream's removal was deliberate — the commit message removed PlantUML installs across the fleet, not just an individual action, and provided no replacement.

Conclusion: straight step deletion. If any future model repo needs PlantUML, a per-repo step can add it, but the shared reusable doesn't need to carry the install.

Not a required check, but

The failing leg has been red on every PR run for ~11 months. Merges have been proceeding because the check isn't required, but the standing red masks genuine failures — anyone reviewing a PR sees red and has to check whether it's this-known-issue-or-something-real every time. Getting green back gives PR reviewers back the signal.

🤖