generate requirements.txt by `pip-compile`

requirements.txt

-#click==6.7
-numpy==1.14.0
-pillow==5.3.0
-mxnet==1.4.1
-gluoncv==0.3.0
-#opencv-python==3.4.4.19
+#
+# This file is autogenerated by pip-compile
+# To update, run:
+#
+#    pip-compile --output-file=requirements.txt
+#
+--index-url https://pypi.doubanio.com/simple
+
+certifi==2020.4.5.1       # via requests
+chardet==3.0.4            # via requests
+cycler==0.10.0            # via matplotlib
+gluoncv==0.6.0            # via cnocr (setup.py)
+graphviz==0.8.4           # via mxnet
+idna==2.9                 # via requests
+kiwisolver==1.2.0         # via matplotlib
+matplotlib==3.2.1         # via gluoncv
+mxnet==1.6.0              # via cnocr (setup.py)
+numpy==1.18.3             # via cnocr (setup.py), gluoncv, matplotlib, mxnet, scipy
+pillow==5.3.0             # via cnocr (setup.py), gluoncv
+pyparsing==2.4.7          # via matplotlib
+python-dateutil==2.8.1    # via matplotlib
+requests==2.23.0          # via gluoncv, mxnet
+scipy==1.4.1              # via gluoncv
+six==1.14.0               # via cycler, python-dateutil
+tqdm==4.45.0              # via gluoncv
+urllib3==1.25.9           # via requests