Fix doc (#8)

* Update doc requirements

* Resolve API issue in readthedocs

* Fix package order

* Update requirements

* Update sphinx

* Add mock

.readthedocs.yml

+version: 2
+
+python:
+  version: 3.7
+  install:
+    - requirements: requirements/docs.txt
+    - requirements: requirements/build.txt
+    - requirements: requirements/runtime.txt
+    - requirements: requirements/readthedocs.txt

docs/conf.py

@@ -47,7 +47,8 @@ autodoc_mock_imports = [
     'mmdet3d.ops.ball_query', 'mmdet3d.ops.furthest_point_sample',
     'mmdet3d.ops.gather_points', 'mmdet3d.ops.group_points',
     'mmdet3d.ops.interpolate', 'mmdet3d.ops.roiaware_pool3d',
-    'mmdet3d.ops.spconv', 'mmdet3d.ops.voxel.voxel_layer', 'mmdet3d.ops.iou3d'
+    'mmdet3d.ops.spconv', 'mmdet3d.ops.voxel.voxel_layer', 'mmdet3d.ops.iou3d',
+    'mmdet3d.ops.utils'
 ]
 autosectionlabel_prefix_document = True
 

docs/requirements.txt → requirements/docs.txt

 m2r
 recommonmark
-sphinx
+sphinx==3.1.2
 sphinx_markdown_tables
 sphinx_rtd_theme

requirements/readthedocs.txt

+mmcv
+torch
+torchvision
+git+https://github.com/open-mmlab/mmdetection.git