ci: Fix the failing run-lint step

Fix the failing run-lint test by switching to Debian Bookworm for this
step, and installing Poetry 1.2.2 from the official repos. This way, we
circumvent a bug [1] in Poetry 1.3 (released on PyPI) and we greatly
simplify this step [2].

[1]: https://github.com/python-poetry/poetry/issues/7184
[2]: https://github.com/freedomofpress/dangerzone/issues/292#issuecomment-1351368122

.circleci/config.yml

@@ -70,25 +70,21 @@ aliases:
 jobs:
   run-lint:
     docker:
-      - image: debian:bullseye
+      - image: debian:bookworm
     resource_class: small
     steps:
       - checkout
       - run:
           name: Install dev. dependencies
+          # Install only the necessary packages to run our linters.
           command: |
             export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true
             apt-get update
-            apt-get install -y make python3 python3-pip python3-venv
+            apt-get install -y make python3 python3-poetry --no-install-recommends
-            python3 -m venv .venv
+            poetry install --only lint
-            source .venv/bin/activate
-            pip install poetry
-            poetry install  # FIXME --dev-only once poetry 1.2.0 is out https://github.com/python-poetry/poetry/issues/2572
       - run:
           name: Run linters to enforce code style
-          command: |
+          command: poetry run make lint
-            source .venv/bin/activate
-            make lint
 
   build-container-image:
     working_directory: /app