xcb: add Vulkan init to sample

packages/xcb/build.zig

@@ -4,6 +4,14 @@ pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
+    const vulkan_dep = b.dependency("vulkan_zig", .{
+        .target = target,
+        .optimize = optimize,
+        .registry = b.path("vendor/vk.xml"),
+    });
+
+    const vulkan_mod = vulkan_dep.module("vulkan-zig");
+
     const mod = b.addModule("xcb", .{
         .root_source_file = b.path("src/root.zig"),
         .target = target,
@@ -27,6 +35,7 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
         .imports = &.{
+            .{ .name = "vulkan", .module = vulkan_mod },
             .{ .name = "xcb", .module = mod },
         },
     });