PyGPU: expose 'GPU_SHADER_3D_IMAGE_COLOR'

This shader is required by some addons that need to modulate the alpha of images.

source/blender/python/gpu/gpu_py_shader.c

@@ -37,6 +37,9 @@
   "``IMAGE``\n" \
   "   :Attributes: vec3 pos, vec2 texCoord\n" \
   "   :Uniforms: sampler2D image\n" \
+  "``IMAGE_COLOR``\n" \
+  "   :Attributes: vec3 pos, vec2 texCoord\n" \
+  "   :Uniforms: sampler2D image, vec4 color\n" \
   "``SMOOTH_COLOR``\n" \
   "   :Attributes: vec3 pos, vec4 color\n" \
   "   :Uniforms: none\n" \
@@ -56,6 +59,7 @@
 static const struct PyC_StringEnumItems pygpu_shader_builtin_items[] = {
     {GPU_SHADER_3D_FLAT_COLOR, "FLAT_COLOR"},
     {GPU_SHADER_3D_IMAGE, "IMAGE"},
+    {GPU_SHADER_3D_IMAGE_COLOR, "IMAGE_COLOR"},
     {GPU_SHADER_3D_SMOOTH_COLOR, "SMOOTH_COLOR"},
     {GPU_SHADER_3D_UNIFORM_COLOR, "UNIFORM_COLOR"},
     {GPU_SHADER_3D_POLYLINE_FLAT_COLOR, "POLYLINE_FLAT_COLOR"},