gitlab-ci.yml: fix pip command with alpine 3.19

Put the argument at the right place.

.gitlab-ci.yml

@@ -30,7 +30,7 @@ flake8:
   image: "alpine:latest"
   before_script:
   - "apk -q add py3-pip"
-  - "pip3 -q --disable-pip-version-check --break-system-packages install flake8"
+  - "pip3 -q --disable-pip-version-check install flake8 --break-system-packages"
   script:
   - ".ci/flake8.sh"