ci: hardcode target_amd64 for a while in the build-linux-kernel workf…

…low to emulate previously used behavior

Signed-off-by: Misha Sakhnov <[email protected]>

.github/workflows/vm-kernel.yaml

@@ -194,6 +194,9 @@ jobs:
           build-args: KERNEL_VERSION=${{ steps.get-kernel-version.outputs.VM_KERNEL_VERSION }}
           context: neonvm/hack/kernel
           platforms: linux/amd64
+          # neonvm/hack/kernel/Dockerfile.kernel-builder has different targets for different architectures
+          # so we need to specify the target explicitly 
+          target: kernel_amd64
           # Push kernel image only for scheduled builds or if workflow_dispatch/workflow_call input is true
           push: true
           pull: true