bug: 3 json schemas in spec-0.5 and main branch list `context.version` as a required field instead of `context.specversion`

[davidB]

When I was adding support of spec 0.5 to sdk-rust, some test failed: test that validate conformance/*.json against json schema.

• spec/schemas/pipelinerunfinished.json

  Line 44 in b96af53

  "required": ["version", "id", "source", "type", "timestamp"]

• spec/schemas/testcaserunfinished.json

  Line 43 in b96af53

  "required": ["version", "id", "source", "type", "timestamp"]

• spec/schemas/testsuiterunfinished.json

  Line 43 in b96af53

  "required": ["version", "id", "source", "type", "timestamp"]

I'll work on the fix in a PR against main branch:

• find why spec's CI didn't detect the issue
• fix the json schema

Then the fix will need to be backported to a 0.5.1 release.

EDIT: in fact the CI detect the issue (see the log of "Run validate" at https://github.com/cdevents/spec/actions/runs/20437134172/job/58721108459?pr=281), but doesn't escaladate the error (bash limitation)

[davidB]

@afrittoli, it's blocker (no urgency) for the update of rust SDK (you can track progress at cdevents/sdk-rust#62)