use optional dependencies

Summary:
shapely seems hard to install on windows, and it's not often required.
Therefore make it optional.

Reviewed By: takatosp1

Differential Revision: D18058677

fbshipit-source-id: 3dad50fe75f47ec5450a3732197f3c966d458361

Author: ppwwyyxx

setup.cfg

@@ -3,7 +3,7 @@ line_length=100
 multi_line_output=4
 known_standard_library=numpy,setuptools
 known_myself=detectron2
-known_third_party=fvcore,matplotlib,cv2,torch,torchvision,PIL,pycocotools,yacs,termcolor,cityscapesscripts,tabulate,tqdm,scipy,lvis,torchvision,psutil
+known_third_party=fvcore,matplotlib,cv2,torch,torchvision,PIL,pycocotools,yacs,termcolor,cityscapesscripts,tabulate,tqdm,scipy,lvis,psutil
 no_lines_before=STDLIB,THIRDPARTY
 sections=FUTURE,STDLIB,THIRDPARTY,myself,FIRSTPARTY,LOCALFOLDER
 default_section=FIRSTPARTY

setup.py

@@ -78,9 +78,9 @@ def get_extensions():
         "cloudpickle",
         "matplotlib",
         "tqdm>4.29.0",
-        "shapely",
         "tensorboard",
     ],
+    extras_require={"all": ["shapely", "psutil"]},
     ext_modules=get_extensions(),
     cmdclass={"build_ext": torch.utils.cpp_extension.BuildExtension},
 )