Allow import_playbook from collections (#2018)

examples/playbooks/playbook-parent.yml

@@ -1,3 +1,6 @@
 ---
 - name: Importing another playbook
   ansible.builtin.import_playbook: playbook-imported.yml
+
+- name: Importing playbook from collection
+  import_playbook: community.molecule.validate

requirements.yml

@@ -0,0 +1,5 @@
+---
+collections:
+  # that collection is used during ansible-lint testing for validating our
+  # ability to import_playbook from a collection.
+  - name: community.molecule

src/ansiblelint/utils.py

@@ -24,6 +24,7 @@
 import inspect
 import logging
 import os
+import re
 import warnings
 from argparse import Namespace
 from collections.abc import ItemsView
@@ -72,6 +73,7 @@
 # string as the password to enable such yaml files to be opened and parsed
 # successfully.
 DEFAULT_VAULT_PASSWORD = "x"
+COLLECTION_PLAY_RE = re.compile(r"^[\w\d_]+\.[\w\d_]+\.[\w\d_]+$")
 
 PLAYBOOK_DIR = os.environ.get("ANSIBLE_PLAYBOOK_DIR", None)
 
@@ -288,6 +290,11 @@ def _include_children(
     ):
         v = v["file"]
 
+    if "import_playbook" in k and COLLECTION_PLAY_RE.match(v):
+        # Any import_playbooks from collections should be ignored as ansible
+        # own syntax check will handle them.
+        return []
+
     # handle include: filename.yml tags=blah
     # pylint: disable=unused-variable
     (command, args, kwargs) = tokenize(f"{k}: {v}")