ci: fix Python test by using a non-structural resource

Fixes #98

The ACL resource is what Pulumi would consider a "structural resource", see:
- pulumi/pulumi#918

This kind of resource is not quite correctly handled in the object model, and
this interacts poorly with the upstream provider requiring the ACL to exactly
match the default for "create" to succeed.

It's a reasonable safety precaution of the upstream provider, so it's better to
work around that by using a regular resource in the test.

examples/py-acl/__main__.py

@@ -1,14 +1,5 @@
 """A Python Pulumi program"""
 
-import json
 import pulumi_tailscale as tailscale
 
-acl = tailscale.Acl("demo-py",
-                    acl=json.dumps({
-                        "ACLs": [{
-                            "action": "accept",
-                            "users": ["*"],
-                            "ports": ["*:*"],
-                        }]
-                    }))
-
+tailscale.TailnetKey("demo-py")