examples: workaround fix for testing unified entry point

examples/triangle/main.zig

@@ -4,7 +4,7 @@ const gpu = @import("gpu");
 
 const App = mach.App(*FrameParams, .{});
 
-pub fn main() !void {
+pub fn init() !void {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     var allocator = gpa.allocator();
 
@@ -78,6 +78,12 @@ pub fn main() !void {
     try app.run(.{ .frame = frame });
 }
 
+pub fn update() !bool {
+    return false;
+}
+
+pub fn deinit() void {}
+
 const FrameParams = struct {
     pipeline: gpu.RenderPipeline,
     queue: gpu.Queue,