Remove dependency on 'virtualenv'

'virtualenv' is an external dependency with the same purpose of Python's
'venv' module. This patch removes the external dependency in favor of
the readily available package.

.github/workflows/ansible-test.yml

@@ -11,7 +11,5 @@ jobs:
       - uses: actions/checkout@v3.1.0
         with:
           fetch-depth: 0
-      - name: Install virtualenv using pip
-        run: pip install virtualenv
       - name: Run ansible-test
         run: bash tests/sanity/sanity.sh

tests/sanity/sanity.sh

@@ -8,7 +8,7 @@ ANSIBLE_COLLECTION=freeipa-ansible_freeipa
 
 use_docker=$(docker -v >/dev/null 2>&1 && echo "True" || echo "False")
 
-virtualenv "$VENV"
+python -m venv "$VENV"
 # shellcheck disable=SC1091
 source "$VENV"/bin/activate