Amazon SES: use SES v2 API by default

- Rename `anymail.backends.amazon_sesv2.EmailBackend`
  to `amazon_ses`, making SES v2 the default.
- Rename the old `amazon_ses` backend to `amazon_sesv1`,
  keeping it available. Add a deprecation warning.
- Alias `amazon_sesv2` to `amazon_ses`, with a
  deprecation warning (for projects that opted
  into v2 early under Anymail 9.1 or 9.2).
- Similar renaming on the test files.
- Update docs to assume v2 in most places
  (other than migration-specific sections)

tests/test_amazon_ses_integration.py

@@ -1,6 +1,5 @@
 import os
 import unittest
-import warnings
 from email.utils import formataddr
 
 from django.test import SimpleTestCase, override_settings, tag
@@ -68,7 +67,7 @@ class AmazonSESBackendIntegrationTests(AnymailTestMixin, SimpleTestCase):
 
     def setUp(self):
         super().setUp()
-        self.from_email = "test@%s" % ANYMAIL_TEST_AMAZON_SES_DOMAIN
+        self.from_email = f"test@{ANYMAIL_TEST_AMAZON_SES_DOMAIN}"
         self.message = AnymailMessage(
             "Anymail Amazon SES integration test",
             "Text content",
@@ -77,16 +76,6 @@ class AmazonSESBackendIntegrationTests(AnymailTestMixin, SimpleTestCase):
         )
         self.message.attach_alternative("<p>HTML content</p>", "text/html")
 
-        # boto3 relies on GC to close connections. Python 3 warns about unclosed
-        # ssl.SSLSocket during cleanup. We don't care. (It may be a false positive,
-        # or it may be a botocore problem, but it's not *our* problem.)
-        # https://github.com/boto/boto3/issues/454#issuecomment-586033745
-        # Filter in TestCase.setUp because unittest resets the warning filters
-        # for each test. https://stackoverflow.com/a/26620811/647002
-        warnings.filterwarnings(
-            "ignore", message=r"unclosed <ssl\.SSLSocket", category=ResourceWarning
-        )
-
     def test_simple_send(self):
         # Example of getting the Amazon SES send status and message id from the message
         sent_count = self.message.send()
@@ -129,6 +118,7 @@ class AmazonSESBackendIntegrationTests(AnymailTestMixin, SimpleTestCase):
             headers={"X-Anymail-Test": "value"},
             metadata={"meta1": "simple_string", "meta2": 2},
             tags=["Re-engagement", "Cohort 12/2017"],
+            envelope_sender=f"bounce-handler@{ANYMAIL_TEST_AMAZON_SES_DOMAIN}",
         )
         message.attach("attachment1.txt", "Here is some\ntext for you", "text/plain")
         message.attach("attachment2.csv", "ID,Name\n1,Amy Lina", "text/csv")
@@ -149,14 +139,16 @@ class AmazonSESBackendIntegrationTests(AnymailTestMixin, SimpleTestCase):
 
     def test_stored_template(self):
         # Using a template created like this:
-        # boto3.client('ses').create_template(Template={
-        #     "TemplateName": "TestTemplate",
-        #     "SubjectPart": "Your order {{order}} shipped",
-        #     "HtmlPart": "<h1>Dear {{name}}:</h1>"
+        # boto3.client('sesv2').create_email_template(
+        #     TemplateName="TestTemplate",
+        #     TemplateContent={
+        #         "Subject": "Your order {{order}} shipped",
+        #         "Html": "<h1>Dear {{name}}:</h1>"
         #                 "<p>Your order {{order}} shipped {{ship_date}}.</p>",
-        #     "TextPart": "Dear {{name}}:\r\n"
+        #         "Text": "Dear {{name}}:\r\n"
         #                 "Your order {{order}} shipped {{ship_date}}."
-        # })
+        #     },
+        # )
         message = AnymailMessage(
             template_id="TestTemplate",
             from_email=formataddr(("Test From", self.from_email)),