Update OpenChain Telco SBOM Specification.md

[Jimmy-ahlberg]

Adding a reference to SPDX light that as of v 2.3 fulfills the requirements. Leaving for us to discuss if there are other additional information we would like to see in a "Telco Profile" or if SPDX light is sufficient.

[Jimmy-ahlberg]

Do we create an incompatibility here since section 3.3 refers to version 2.2 and version 2.3 is the one that contains Annex G with the updated SPDX light?

[vargenau]

I would not speak about SPDX Light in our document. We have specified the mandatory elements differently than SPDX Light.