CI: use python3

Python 2 is no longer available:

   W: https://download.docker.com/linux/ubuntu/dists/jammy/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.
   E: Package 'python' has no installation candidate

Author: pohly

.circleci/config.yml

@@ -6,8 +6,8 @@ jobs:
       - image: cimg/go:1.19.5
     steps:
       - checkout
-      - run: sudo apt-get update && sudo apt-get -y -qq install python pip
-      - run: pip install pre-commit
+      - run: sudo apt-get update && sudo apt-get -y -qq install python3 python3-pip
+      - run: pip3 install pre-commit
       - run: SKIP=no-commit-to-branch pre-commit run -a
       - run: go test ./...
       - run: make test