std.Target: bump vulkan max version to 1.4.321

Author: alexrp

lib/std/Target.zig

@@ -646,7 +646,7 @@ pub const Os = struct {
                 .vulkan => .{
                     .semver = .{
                         .min = .{ .major = 1, .minor = 2, .patch = 0 },
-                        .max = .{ .major = 1, .minor = 4, .patch = 313 },
+                        .max = .{ .major = 1, .minor = 4, .patch = 321 },
                     },
                 },
             };