Bump GLFW due to an error on macOS with CMake 3.19.0 (#1657)

cmake/LibiglDownloadExternal.cmake

@@ -94,7 +94,7 @@ endfunction()
 function(igl_download_glfw)
 	igl_download_project(glfw
 		GIT_REPOSITORY https://github.com/glfw/glfw.git
-		GIT_TAG        3.3
+		GIT_TAG        3327050ca66ad34426a82c217c2d60ced61526b7
 		${LIBIGL_BRANCH_OPTIONS}
 	)
 endfunction()