Update schema.md

[Jamesbarford]

Updates the schema.md to the newer formatting we were using. I have a couple of questions;

• Do we still use collector_progress? (answered - no we do not use it in the new system)
• Do we still use artifact_collection_duration?
• What is cache in raw_self_profile?
• Is include in the pull_request_build table a comma separated string of options?
• Is exclude in the pull_request_build table a comma separated string of options?

[Kobzol]

Do we still use artifact_collection_duration?

Not in the new system, but probably some code still reads it.

What is cache in raw_self_profile?

cache is the older name for scenario.

Is include in the pull_request_build table a comma separated string of options?

Yes to both include and exclude.

[Kobzol]

Thanks! Left a few comments.