Deprecate the support for python3.6 (#2525)

* [Fix] Adjust the minimum supported version of Python to 3.6

* refine the docs

.circleci/test.yml

@@ -231,7 +231,7 @@ workflows:
           name: minimum_version_cpu
           torch: 1.6.0
           torchvision: 0.7.0
-          python: 3.6.9  # The lowest python 3.6.x version available on CircleCI images
+          python: 3.7.4
           requires:
             - build_without_ops
       - build_cpu:

.github/workflows/build_macos_wheel.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       matrix:
         torch: [1.6.0, 1.7.0, 1.8.0, 1.9.0, 1.10.0, 1.11.0, 1.12.0, 1.13.0]
-        python-version: [3.6, 3.7, 3.8, 3.9, '3.10']
+        python-version: [3.7, 3.8, 3.9, '3.10']
         include:
           - torch: 1.6.0
             torchvision: 0.7.0
@@ -46,12 +46,6 @@ jobs:
             python-version: '3.10'
           - torch: 1.10.0
             python-version: '3.10'
-          - torch: 1.11.0
-            python-version: 3.6
-          - torch: 1.12.0
-            python-version: 3.6
-          - torch: 1.13.0
-            python-version: 3.6
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python

.github/workflows/merge_stage_test.yml

@@ -81,7 +81,7 @@ jobs:
     runs-on: ubuntu-18.04
     strategy:
       matrix:
-        python-version: [3.6, 3.8, 3.9]
+        python-version: [3.8, 3.9]
         torch: [1.8.1]
         include:
           - torch: 1.8.1

README.md

@@ -49,7 +49,7 @@ It supports the following systems:
 
 See the [documentation](http://mmcv.readthedocs.io/en/2.x) for more features and usage.
 
-Note: MMCV requires Python 3.6+.
+Note: MMCV requires Python 3.7+.
 
 ## Installation
 

README_zh-CN.md

@@ -49,7 +49,7 @@ MMCV 支持多种平台，包括：
 
 如想了解更多特性和使用，请参考[文档](http://mmcv.readthedocs.io/zh_CN/2.x)。
 
-提示: MMCV 需要 Python 3.6 以上版本。
+提示: MMCV 需要 Python 3.7 以上版本。
 
 ## 安装
 

setup.py

@@ -309,7 +309,6 @@ setup(
         'License :: OSI Approved :: Apache Software License',
         'Operating System :: OS Independent',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
@@ -326,6 +325,7 @@ setup(
         'build': parse_requirements('requirements/build.txt'),
         'optional': parse_requirements('requirements/optional.txt'),
     },
+    python_requires='>=3.7',
     ext_modules=get_extensions(),
     cmdclass=cmd_class,
     zip_safe=False)