feat: Force use of pip3 to install python packages.

This should be a no-op in most cases, but for older
installations where it isn't the default, forces the use.

playbooks/roles/common/tasks/main.yml

@@ -169,6 +169,7 @@
     name: "{{ common_pip_pkgs }}"
     state: present
     extra_args: "-i {{ COMMON_PYPI_MIRROR_URL }}"
+    executable: pip3
   when: ansible_distribution in common_debian_variants