Added descriptor_heap sample

samples/descriptor_heap/shaders/heap_triangle.frag

@@ -0,0 +1,9 @@
+#version 450
+
+#pragma shader_stage(fragment)
+
+layout(location = 0) out vec4 outColor;
+
+void main() {
+    outColor = vec4(0.f, 1.f, 0.f, 1.f);
+}

samples/descriptor_heap/shaders/heap_triangle.vert

@@ -0,0 +1,16 @@
+#version 450
+#pragma shader_stage(vertex)
+
+in layout(location=0) vec2 position;
+
+layout(set=0, binding=0) uniform data {
+  vec4 positions[3];
+} vertexData;
+
+void main() {
+    // gl_Position = vec4(positions[gl_VertexIndex], 0.0, 1.0);
+    // gl_Position = vec4(position, 0.0, 1.0);
+    // gl_Position = vec4(inputData.positions[gl_VertexIndex], 0.0, 1.0);
+    gl_Position = vertexData.positions[gl_VertexIndex];
+    // gl_Position = vec4(position, 0.0, 1.0);
+}