Pin ansible-core to earlier than 2.16.3

ansible-core 2.16.3 and later suffer from the bug discussed in
ansible/ansible#82702, which breaks any symlinked files in vars,
tasks, etc. for any Ansible role installed via ansible-galaxy.

requirements-test.txt

@@ -8,6 +8,15 @@
 # We need at least version 6 to correctly identify Amazon Linux 2023
 # as using the dnf package manager.
 ansible>=6,<7
+# TODO: Remove this pin when possible.  See
+# cisagov/skeleton-ansible-role#178 for more details.
+#
+# ansible-core 2.16.3 and later suffer from the bug discussed in
+# ansible/ansible#82702, which breaks any symlinked files in vars,
+# tasks, etc. for any Ansible role installed via ansible-galaxy.
+#
+# See also cisagov/skeleton-packer##312.
+ansible-core<2.16.3
 # With the release of molecule v5 there were some breaking changes so
 # we need to pin at v5 or newer. However, v5.0.0 had an internal
 # dependency issue so we must use the bugfix release as the actual