Update RGC URN in tracking section to match RGC CTL reference implementation

[reinecke]

In the Reference Gamut Compression Specification, the Tracking section of the document states the following URN: urn:ampas:aces:transformId:v1.5:LMT.Academy.GamutCompress.a1.3.0

However, in the CTL Reference implementation, this URN is used: urn:ampas:aces:transformId:v1.5:LMT.Academy.ReferenceGamutCompress.a1.v1.0

This PR updates the tracking section to be in-line with the reference implementation and current guidance about which URN should be used.

[CLAassistant]

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