flake8 fails on python3.6

.github/workflows/ci.yaml

@@ -23,6 +23,8 @@ jobs:
         python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
         os: ["ubuntu-latest", "ubuntu-20.04"]
         exclude:
+          - os: ubuntu-latest
+            python-version: "3.6"
           - os: ubuntu-20.04
             python-version: "3.7"
           - os: ubuntu-20.04
@@ -56,7 +58,7 @@ jobs:
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names
-        flake8 . --exclude src/exabgp/vendoring/ --exclude build/ --count --select=E9,F63,F7,F82 --show-source --statistics
+        if [[ $(python3 --version | grep "3.6") ]]; then flake8 . --exclude src/exabgp/vendoring/ --exclude build/ --count --select=E9,F63,F7,F82 --show-source --statistics; fi
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
         # flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics