docs: Mark ARB_shader_image_load_store as work in progress.

Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
diff --git a/docs/GL3.txt b/docs/GL3.txt
index f98a54a..0672ec7 100644
--- a/docs/GL3.txt
+++ b/docs/GL3.txt
@@ -132,7 +132,7 @@
   GL_ARB_texture_storage                               DONE (all drivers)
   GL_ARB_transform_feedback_instanced                  DONE (i965, r600, radeonsi)
   GL_ARB_base_instance                                 DONE (i965, nv50, nvc0, r600, radeonsi)
-  GL_ARB_shader_image_load_store                       not started
+  GL_ARB_shader_image_load_store                       in progress (curro)
   GL_ARB_conservative_depth                            DONE (all drivers that support GLSL 1.30)
   GL_ARB_shading_language_420pack                      DONE (all drivers that support GLSL 1.30)
   GL_ARB_internalformat_query                          DONE (i965, r300, r600, radeonsi)