fix: pdf/a compliance of attachments

[florianbepunkt]

Fixes part of #1561

I followed the contributing guide, but this did not work. All tests failed due to some jest config problem:

Jest encountered an unexpected token

    Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

Is the contributing guide up-to-date?

[liborm85]

Fixed rendering diff in unit tests by commit 3a6977e. Update PR on master upstream.

[liborm85]

I don't know why your local Jest is failing. Commands in contributing guide are correct.

[florianbepunkt]

Rebased based on origin/master.

Regarding the tests: I don't know. There is yarn.lock in the repo, but contributing guide says npm. Jest is complaining about ESM modules. I cloned the master branch, run npm install, npm run build and npm run test. So no changes on my end, just followed the instructions.

[blikblum]

The tests are running fine on CI.

The object tests need to be adapted to handle the added field. See https://github.com/foliojs/pdfkit/actions/runs/11642384173/job/32422370876?pr=1562

[blikblum]

There is yarn.lock in the repo, but contributing guide says npm.

It should use yarn. the contributing must be changed