Update the create_order to replace PSOrthoTile example with PSScene
**Expected behavior**
No examples using PSOrthoTile. create_order example should use PSScene.

**Actual behavior (describe the problem)**
We've been asked to remove PSOrthoTile examples from all content by March 22. This change can happen anytime.

**Related Issues**
Additional changes to codebase will be requested in the documentation or later as part of a dot release. This request is only to change the example in the file: https://github.com/planetlabs/planet-client-python/blob/main/planet/clients/orders.py

**Workaround**
n/a

**Minimum, Complete, Viable Code Sample**
A "Minimal, Complete and Verifiable Example" will make it much easier for maintainers to help you.
See http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports

Replace:

```python
        ...     image_ids = ['3949357_1454705_2020-12-01_241c']
        ...     request = build_request(
        ...         'test_order',
        ...         [product(image_ids, 'analytic', 'psorthotile')]
```

with:

```python
        ...     image_ids = ["20200925_161029_69_2223"]
        ...     request = build_request(
        ...         'test_order',
        ...         [product(image_ids, 'analytic_udm2', 'psscene')]
```

**Environment Information**
* Operation System Information (`python -c "import platform; print(platform.platform())"`)
* Python version (`python -c "import sys; print(sys.version.replace('\\n', ' '))"`)
* Planet package version (`planet -v`)

**Installation Method**
* conda, pip wheel, from source, etc...

diff --git a/planet/clients/orders.py b/planet/clients/orders.py
index d0918c9..584df8d 100644
--- a/planet/clients/orders.py
+++ b/planet/clients/orders.py
@@ -123,10 +123,10 @@ class OrdersClient:
         >>> from planet.order_request import build_request, product
         >>>
         >>> async def main():
-        ...     image_ids = ['3949357_1454705_2020-12-01_241c']
+        ...     image_ids = ["20200925_161029_69_2223"]
         ...     request = build_request(
         ...         'test_order',
-        ...         [product(image_ids, 'analytic', 'psorthotile')]
+        ...         [product(image_ids, 'analytic_udm2', 'psscene')]
         ...     )
         ...     async with Session() as sess:
         ...         cl = OrdersClient(sess)
['planet/clients/orders.py']