Update dependency markdownify to v1

Author: renovate[bot]

pyproject.toml

@@ -13,7 +13,7 @@ dependencies = [
     "python-dotenv>=1.0.0,<2",
     "sentry-sdk>=2.0.0,<3",
     "whitenoise>=6.4.0,<7",
-    "markdownify>=0.14.0,<0.15",
+    "markdownify>=1.2,<1.3",
     "django-markdownify>=0.9.3,<0.10",
     "django-magiclink>=1.2.0,<2",
     "django-anymail>=13.0.0,<14",