fix: properly define primary key

[ctron]

To my understanding that should be a composite primary key:

trustify/migration/src/m0000220_create_package_relates_to_package.rs

Lines 58 to 64 in 3f0719b

	.primary_key(
	Index::create()
	.col(PackageRelatesToPackage::LeftPackageId)
	.col(PackageRelatesToPackage::Relationship)
	.col(PackageRelatesToPackage::RightPackageId)
	.col(PackageRelatesToPackage::SbomId),
	)

And the docs seem to require the attribute for all fields of that key:

https://www.sea-ql.org/SeaORM/docs/generate-entity/entity-structure/#composite-key