expand ci python matrix and add badges

Author: integerQuant

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.10", "3.12"]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
 
     steps:
       - uses: actions/checkout@v4

README.md

@@ -1,5 +1,8 @@
 # ddstats
 
+[![CI](https://github.com/integerQuant/ddstats/actions/workflows/ci.yml/badge.svg)](https://github.com/integerQuant/ddstats/actions/workflows/ci.yml)
+[![PyPI version](https://img.shields.io/pypi/v/ddstats.svg)](https://pypi.org/project/ddstats/)
+
 Fast drawdown & CED metrics in Rust with NumPy bindings.
 
 ## Overview