Add Makefile target for local container tests

It is a small wrapper to run tests in a container with a pinned pylint
version.

The pinned pylint version is required otherwise we would be still fixing
pylint issues on this stable branch.

Use this new call also in the GH action.

Author: jkonecny12

.github/workflows/validate.yml

@@ -9,6 +9,4 @@ jobs:
 
       - name: Run test
         run: |
-          podman run --rm -v .:/simpleline:Z --workdir /simpleline registry.fedoraproject.org/fedora:rawhide sh -c " \
-              dnf install -y python3-pylint python3-gobject-base make; \
-              make ci"
+          make container-ci

Makefile

@@ -147,3 +147,9 @@ pypi-upload:
 
 .PHONY: ci
 ci: check test
+
+# Run tests in the container but with fixed pylint version
+container-ci:
+	podman run --pull=always --rm -v .:/simpleline:Z --workdir /simpleline quay.io/centos/centos:stream9 sh -c " \
+	dnf install -y python3-pip python3-gobject-base make && pip3 install pocketlint 'pylint==2.8.3' ; \
+	make ci"