Drop support of Python 3.6 (#351)

* Update README.md

* Update DESCRIPTION

* Update Readme.rst

* Update setup.py

* Update main.yml

Author: StrikerRUS

.github/workflows/main.yml

@@ -22,13 +22,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-latest
-            container: ubuntu:trusty
-            python_version: 3.6
-          - os: macos-latest
-            python_version: 3.6
-          - os: windows-2016
-            python_version: 3.6
           - os: ubuntu-latest
             container: ubuntu:trusty
             python_version: 3.7

R-package/DESCRIPTION

@@ -8,7 +8,7 @@ BugReports: https://github.com/RGF-team/rgf/issues
 URL: https://github.com/RGF-team/rgf/tree/master/R-package
 Description: Regularized Greedy Forest wrapper of the 'Regularized Greedy Forest' <https://github.com/RGF-team/rgf/tree/master/python-package> 'python' package, which also includes a Multi-core implementation (FastRGF) <https://github.com/RGF-team/rgf/tree/master/FastRGF>.
 License: MIT + file LICENSE
-SystemRequirements: Python (>= 3.6), rgf_python, scikit-learn (>= 0.18.0), scipy, numpy. Detailed installation instructions for each operating system can be found in the README file.
+SystemRequirements: Python (>= 3.7), rgf_python, scikit-learn (>= 0.18.0), scipy, numpy. Detailed installation instructions for each operating system can be found in the README file.
 Depends:
     R(>= 3.2.0)
 Imports:

R-package/README.md

@@ -35,7 +35,7 @@ The **RGF** package is a wrapper of the [Regularized Greedy Forest (RGF)](https:
 
 <br>
 
-* Python (>= 3.6)
+* Python (>= 3.7)
 
 
 <br>

python-package/Readme.rst

@@ -54,7 +54,7 @@ Examples of using FastRGF estimators could be found `here <https://github.com/RG
 Software Requirements
 ---------------------
 
--  Python (>= 3.6)
+-  Python (>= 3.7)
 -  joblib
 -  scikit-learn (>= 0.18)
 

python-package/setup.py

@@ -389,7 +389,6 @@ def run(self):
                    'Operating System :: POSIX',
                    'Operating System :: Unix',
                    'Programming Language :: Python :: 3',
-                   'Programming Language :: Python :: 3.6',
                    'Programming Language :: Python :: 3.7',
                    'Programming Language :: Python :: 3.8',
                    'Programming Language :: Python :: 3.9',