✔ CircleCI: Do not test on Python 3.6 anymore (EOL since 2021-12-23)

(See also #90 where it came up.)

.circleci/config.yml

@@ -15,7 +15,6 @@ jobs:
     steps:
       - checkout
       - run: pip3 install --upgrade pip
-      - run: if python3 --version | grep -q "Python 3.6"; then pip install --prefer-binary -U opencv-python-headless numpy; fi  # to avoid compilation
       - run: make install deps-test-ubuntu PIP_INSTALL="pip3 install"
       - run: make coverage
       - codecov/upload
@@ -30,4 +29,4 @@ workflows:
                 - screenshots
           matrix:
             parameters:
-              python-image: ["python:3.6", "python:3.7", "python:3.8", "python:3.9", "python:3.10"]
+              python-image: ["python:3.7", "python:3.8", "python:3.9", "python:3.10"]