fix image to use URL
-<div align="center"><img src="docs/image/cupy_logo_1000px.png" width="400"/></div>
+<div align="center"><img src="https://raw.githubusercontent.com/cupy/cupy/master/docs/image/cupy_logo_1000px.png" width="400"/></div>
# CuPy : NumPy-like API accelerated with CUDA
