v10 release would support only CycloneDX 1.5 and 1.6

[prabhu]

In general, we intend to support only two spec versions for every major release. Please plan your upgrade path accordingly.

[prabhu]

Now that we have added support for 1.6, the timer has started for 1.4 deprecation. We will wait till dependency track and depscan adds support for 1.6 before deprecating 1.4

[prabhu]

Dependency track now supports ingesting 1.6 BOM documents. We will deprecate 1.4 beginning with the cdxgen 10.9.x release.

[prabhu]

Shall we go ahead and remove 1.4 support from the project? CycloneDX 1.7 specification is due this summer, so we can prioritise the future instead of the past.