.github/ci: Install python3-packaging package

show-fixed-kernel-cves.py script from flatcar-build-scripts requires
this package:

Traceback (most recent call last):
  File "/home/runner/actions-runner/_work/scripts/scripts/flatcar-build-scripts/show-fixed-kernel-cves.py", line 29, in <module>
    from packaging import version
ModuleNotFoundError: No module named 'packaging'

.github/workflows/ci.yaml

@@ -55,7 +55,7 @@ jobs:
           sudo rm /bin/sh
           sudo ln -s /bin/bash /bin/sh
           sudo apt-get update
-          sudo apt-get install -y ca-certificates curl git gnupg lsb-release python3 qemu-user-static zstd
+          sudo apt-get install -y ca-certificates curl git gnupg lsb-release python3 python3-packaging qemu-user-static zstd
           sudo mkdir -p /etc/apt/keyrings
           curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
           echo \