Drop Python 3.6 support (#57)

* Update tests.yml

* Update setup.py

.github/workflows/tests.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python_version: ["3.6", "3.7", "3.8"]
+        python_version: ["3.7", "3.8"]
         featuretools_version: ["Release", "Main"]
     steps:
       - name: Set up python ${{ matrix.python_version }}
@@ -37,7 +37,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python_version: ["3.6", "3.7", "3.8"]
+        python_version: ["3.7", "3.8"]
     steps:
       - name: Set up python ${{ matrix.python_version }}
         uses: actions/setup-python@v2
@@ -61,7 +61,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python_version: ["3.6", "3.7", "3.8"]
+        python_version: ["3.7", "3.8"]
         featuretools_version: ["Release", "Main"]
     steps:
       - name: Set up python ${{ matrix.python_version }}
@@ -89,7 +89,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python_version: ["3.6", "3.7", "3.8"]
+        python_version: ["3.7", "3.8"]
     steps:
       - name: Set up python ${{ matrix.python_version }}
         uses: actions/setup-python@v2

setup.py

@@ -19,6 +19,13 @@
     version='1.1.0',
     author='Feature Labs, Inc.',
     author_email='[email protected]',
+    classifiers=[
+         'Development Status :: 3 - Alpha',
+         'Intended Audience :: Developers',
+         'Programming Language :: Python :: 3',
+         'Programming Language :: Python :: 3.7',
+         'Programming Language :: Python :: 3.8'
+    ],
     license='BSD 3-clause',
     url='http://www.featurelabs.com/',
     install_requires=open('requirements.txt').readlines(),
@@ -27,7 +34,7 @@
     zip_safe=False,
     long_description=long_description,
     long_description_content_type='text/markdown',
-    python_requires='>=3.6',
+    python_requires='>=3.7, <4',
     extras_require=extras_require,
     entry_points={
         'featuretools_plugin': [