examples: add pub_bytes

This was the point that I realized there's no reason to have the string
variants of the publishing methods. But also there's not really much
point in porting the other getting-started examples, since we've
covered all their functionality in the existing examples
(actually, this one is redundant too, but I have already done it, so
it's getting grandfathered in).

Porting some of the more interesting examples might be a good idea, but
those have a weird argument parser that I don't really want to port
(even though it is very simple in the way that it works). For the most
part, I think writing unit tests will do a better of flexing the
bindings.

build.zig

@@ -54,6 +54,7 @@ const Example = struct {
 const examples = [_]Example{
     .{ .name = "request_reply", .file = "examples/request_reply.zig" },
     .{ .name = "headers", .file = "examples/headers.zig" },
+    .{ .name = "pub_bytes", .file = "examples/pub_bytes.zig" },
 };
 
 pub fn add_examples(b: *std.build, options: ExampleOptions) void {