use GitHub Actions instead of Travis to run linters

.github/workflows/lint.yml

@@ -0,0 +1,24 @@
+name: Linter
+on:
+  pull_request: 
+    branches: [ master ]
+  push:
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v1
+        with:
+          python-version: 3.8
+      - name: Install Linters
+        run: pip3 install flake8 isort black
+      - name: flake8
+        run: flake8 *.py
+      - name: isort
+        run: isort -c -df *.py
+      - name: black
+        run: black --check --diff *.py

run.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 
-import argparse
 import sys
+import argparse
 from typing import List, Tuple
 
 import testcases
@@ -33,9 +33,7 @@ def get_args():
             default=False,
             help="turn on debug logs",
         )
-        parser.add_argument(
-            "-s", "--server", help="server implementations (comma-separated)"
-        )
+        parser.add_argument("-s", "--server", help="server implementations (comma-separated)")
         parser.add_argument(
             "-c", "--client", help="client implementations (comma-separated)"
         )