zigrtiow: alloc image on heap to enable larger images.

zigrtiow/src/main.zig

@@ -106,7 +106,7 @@ pub fn main() anyerror!void {
     const Node = Queue(Task).Node;
     const allocator = std.heap.page_allocator;
     const cpus = try Thread.getCpuCount();
-    var pixels: [image_width * image_height]Color = undefined;
+    var pixels = try allocator.create([image_width * image_height]Color);
     var q = Queue(Task).init();
     var threads: std.ArrayList(std.Thread) = std.ArrayList(std.Thread).init(allocator);
     var row: usize = 0;