[3.0] Use MAJOR.MINOR version JSON-LD context URL in example

[bact]

This PR targets support/3.0 branch. A similar PR for develop is at #1244

To use "3.0" RDF URLs (version without patch version), as required by https://github.com/spdx/spdx-3-model/issues/1046, we need to verify if new RDF URLs are working.

We may check that with an SBOM example (examples/jsonld/package_sbom.json) and the example validation workflow in this repo.

This issue may not directly affect the texts in the ISO publication but without the fix the texts in ISO publication may not back with relevant working URLs.

• See https://github.com/spdx/spdx-3-model/issues/1046 (ISO issue)

[bact]

The example validation failed, because https://spdx.org/schema/3.0/spdx-json-schema.json is not exist yet.

• Need to fix this issue first #1246

[goneall]

The URL now appears to work - @bact - can you re-trigger the CI - perhaps by rebasing - and see if it passes?

[bact]

We don't yet have a clear path to republish support/3.0 yet.

As I understand, if we are still in 3.0.x and don't have 3.1 yet, do we have to push support/3.0 to main first?

[goneall]

We don't yet have a clear path to republish support/3.0 yet.

As I understand, if we are still in 3.0.x and don't have 3.1 yet, do we have to push support/3.0 to main first?

@bact - do we need to resolve the republish issue to merge this PR? If not, I just want to make sure the CI passes and I can't re-trigger it myself.