update flake8 setup

.github/workflows/main.yaml

@@ -13,11 +13,13 @@ jobs:
         uses: actions/checkout@v5.0.0
 
       - name: Run tests
-        run: python3 test_main.py
+        run: |
+          python3 test_main.py
 
       - name: setup pyflake8
         run: |
-          python -m pip install flake8
+          apt update
+          apt install flake8 -y
 
-      - name: run pyflake8
+      - name: run flake8
         run: flake8 .

test_main.py

@@ -8,7 +8,7 @@ class TestCalculator(unittest.TestCase):
         self.assertEqual(add(-1, 1), 0)
 
     def test_subtract(self):
-        self.assertEqual(subtract(5, 2), 2)
+        self.assertEqual(subtract(5, 2), 3)
         self.assertEqual(subtract(0, 1), -1)