Update test for milestone 2.18 (#4237)

For unknown reason, the behaviour of milestone differs such that the PWD
environment variable is not updated to the directory of the process.

Because we are not running with a shell and it's the shell's
resposbility to keep it updated, we'll switch instead to a lookup pipe
to get the pwd and not rely on the env var.

After several hours of digging without success, this should accomplish
what the test intended todo with a dependency on the shell.

tests/fixtures/integration/test_command/molecule/smoke/converge.yml

@@ -1,11 +1,14 @@
+---
 - name: Converge
   hosts: localhost
   connection: local
   tasks:
     - name: Assert CWD is the same as playbook_dir
       ansible.builtin.assert:
         that:
-          - playbook_dir == lookup('env', 'PWD')
+          - playbook_dir == pwd
         msg: >
           Molecule should automatically chdir to scenario directory {{ playbook_dir }}
-          but we found that it runs from {{ lookup('env', 'PWD') }} instead."
+          but we found that it runs from {{ pwd }} instead."
+      vars:
+        pwd: "{{ lookup('pipe', 'pwd') }}"