CI/CD: Support Django 5.1 release

- Change Django 5.1 install from pre-release to release.
- Add Python 3.13 testing for Django 5.2dev

tox.ini

@@ -5,12 +5,14 @@ envlist =
     # Factors: django-python-extras
     # Test lint, docs, earliest/latest Django first, to catch most errors early...
     lint
-    django50-py312-all
+    django51-py312-all
     django30-py37-all
     docs
     # ... then test all the other supported combinations:
+    # Django 5.1: Python 3.10, 3.11, and 3.12
+    django51-py{310,311}-all
     # Django 5.0: Python 3.10, 3.11, and 3.12
-    django50-py{310,311}-all
+    django50-py{310,311,312}-all
     # Django 4.2: Python 3.8, 3.9, 3.10, 3.11
     django42-py{38,39,310,311,py38,py39}-all
     # Django 4.1: Python 3.8, 3.9, 3.10
@@ -24,12 +26,12 @@ envlist =
     # Django 3.0: Python 3.6 (eol 2021-12-23), 3.7, 3.8, 3.9 (added in 3.0.11)
     django30-py{38,39,py38,py39}-all
     # ... then prereleases (if available) and current development:
-    # Django 5.1 alpha: Python 3.10, 3.11, and 3.12
-    django51-py{310,311,312}-all
-    # Django 5.2 dev: Python 3.10, 3.11, and 3.12
-    djangoDev-py{310,311,312}-all
+    # Django 5.2 pre-release: Python 3.10, 3.11, 3.12 and 3.13
+    # django52-py{310,311,312,313}-all
+    # Django 5.2 dev: Python 3.10, 3.11, 3.12 and 3.13
+    djangoDev-py{310,311,312,313}-all
     # ... then partial installation (limit extras):
-    django50-py312-{none,amazon_ses,postal,resend}
+    django51-py312-{none,amazon_ses,postal,resend}
 # tox requires isolated builds to use pyproject.toml build config:
 isolated_build = True
 
@@ -46,7 +48,8 @@ deps =
     django41: django~=4.1.0
     django42: django~=4.2.0
     django50: django~=5.0.0
-    django51: django~=5.1.0a0
+    django51: django~=5.1.0
+    django52: django~=5.2.0a0
     djangoDev: https://github.com/django/django/tarball/main
 extras =
     # Install [esp-name] extras only when testing "all" or esp_name factor.