update changelog for version 2.13.1 via release script

CHANGELOG.md

@@ -2,6 +2,19 @@
 
 Changelogs for versions not listed here can be found at https://github.com/DataDog/dd-trace-py/releases
 
+---
+
+## 2.13.1
+
+
+### Bug Fixes
+
+- library injection: Resolves an issue where the version of `attrs` installed by default on some Ubuntu installations was treated as incompatible with library injection
+- anthropic: Resolves an issue where attempting to tag non-JSON serializable request arguments caused a `TypeError`. The Anthropic integration now safely tags non-JSON serializable arguments with a default placeholder text.
+- postgres: Fixes circular imports raised when psycopg automatic instrumentation is enabled.
+- ASM: This fix resolves an issue where exploit prevention was not properly blocking requests with custom redirection actions.
+
+
 ---
 
 ## 2.11.6