fix: Use forward slashes to construct filepaths for Ansible provisioner

[bdonaldson77]

Fixes the same filepath construction issue that was corrected in the container creation logic by always using forward slashes for filepaths that are accessed inside the container used for testing.

Tests came back clean with these changes on my end:
ok github.com/z0mbix/rolecule/pkg/provisioner 0.256s coverage: 45.9% of statements

Without fix:

   • converging container rolecule-opkssh-ubuntu-systemd with ansible
   • executing interactive command: C:\ProgramData\chocolatey\bin\docker.exe exec --env ANSIBLE_ROLES_PATH=/etc/ansible/roles --env ANSIBLE_NOCOWS=True rolecule-opkssh-ubuntu-systemd ansible-playbook --connection local --inventory localhost, tests\playbook.yml
ERROR! the playbook: tests\playbook.yml could not be found
   ⨯ command failed: exit status 1

With fix:

   • converging container rolecule-opkssh-ubuntu-systemd with ansible
   • executing interactive command: C:\ProgramData\chocolatey\bin\docker.exe exec --interactive --tty --env ANSIBLE_NOCOWS=True --env ANSIBLE_ROLES_PATH=/etc/ansible/roles rolecule-opkssh-ubuntu-systemd ansible-playbook --connection local --inventory localhost, tests/playbook.yml

PLAY [test] ************************************************************************************************************
...

Wrong account