[Docs] Add readthedocs.yml (#501)

* [Docs] Add readthedocs.yml

* include torch in readthedocs.yml

* add torch torchvision in docs.txt

.readthedocs.yml

+version: 2
+
+formats: all
+
+python:
+  version: 3.7
+  install:
+    - requirements: requirements/runtime.txt
+    - requirements: requirements/docs.txt

docs/en/api/utils.rst

@@ -47,7 +47,7 @@ Package
    :template: classtemplate.rst
 
    call_command
-   check_install_package
+   install_package
    get_installed_path
    is_installed
 

docs/zh_cn/api/utils.rst

@@ -45,7 +45,7 @@ Package
    :nosignatures:
 
    call_command
-   check_install_package
+   install_package
    get_installed_path
    is_installed
 

requirements/docs.txt

 docutils==0.16.0
 myst-parser
+opencv-python
 -e git+https://github.com/open-mmlab/pytorch_sphinx_theme.git#egg=pytorch_sphinx_theme
 sphinx==4.0.2
 sphinx-copybutton
 sphinx_markdown_tables
+torch
+torchvision