Dependencies list in Dependency struct should be an array of String, not Dependency

[A.J. Brown]

I opened a similar issue on the Java library. The specification calls for dependsOn to be a list of bom-refs (as string) without nesting, however the struct implies that dependencies can in fact be nested.

cyclonedx-go/cyclonedx.go

Line 223 in 3cc319e

 Dependencies *[]Dependency `xml:"dependency,omitempty"`