Bug#1100751: spirv-headers: please update to 1.4.309.0

[Andreas Beckmann]

Package: spirv-headers
Version: 1.6.1+1.4.304.0-1
Severity: important

Hi,

please update to 1.4.309.0 or later. This version is needed to packaging
newer spirv-llvm-translator versions (from all branches).

Thanks

Andreas