✨ Add modern Python support

Python 3.5 has reached end-of-life, so this commit drops its support and makes
the lib more feasible for modern Python versions.

Author: sprytnyk

.github/workflows/main.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.5, 3.6, 3.7, 3.8]
+        python-version: [3.5, 3.6, 3.7, 3.8, 3.9]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}

plerr/cli.py

@@ -29,21 +29,19 @@ def main():
         '-v',
         '--version',
         action='version',
-        version='plerr v{}'.format(__version__)
+        version=f'plerr v{__version__}'
     )
     args = parser.parse_args()
 
     root = pathlib.Path(__file__).resolve().parent
     try:
-        error = next(root.rglob('*{}.md'.format(args.code.upper())))
+        error = next(root.rglob(f'*{args.code.upper()}.md'))
         content = error.read_bytes()
         print(highlight(content, MarkdownLexer(), TerminalFormatter()))
         sys.exit(0)
     except StopIteration:
         print(
-            'Cannot find {} pylint error by such error code.'.format(
-                args.code
-            ),
+            f'Cannot find {args.code} pylint error by such error code.',
             file=sys.stderr
         )
         sys.exit(1)

setup.py

@@ -28,7 +28,7 @@
     packages=setuptools.find_packages(),
     install_requires=['Pygments==2.8.1'],
     test_suite='plerr.tests.test_package',
-    python_requires='>=3.5',
+    python_requires='>=3.6',
     include_package_data=True,
     keywords=['pylint', 'errors', 'documentation'],
     entry_points={'console_scripts': ['plerr=plerr.cli:main']},
@@ -39,10 +39,10 @@
         'Operating System :: OS Independent',
         'Programming Language :: Python',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: Implementation :: CPython',
         'Topic :: Software Development :: Documentation',
         'Topic :: Software Development :: Libraries :: Python Modules',