Change all references to SSP20 prior to release

[pmai]

Currently the specification and schemas are based on SSP 1.0. To ensure better interoperability all references should be updated to SSP 2.0 prior to release, even though use of SSP Traceability is OK with SSP 1.0 in order to align things like ssc:TAnnotations, etc. with SSP 2.0.

[pmai]

If we release prior to SSP 2.0, then a followup release should be done to align with SSP 2.0.