github: run tests on Python 3.15.

Author: Benjamin Moody

.github/workflows/test.yml

@@ -21,7 +21,7 @@ jobs:
             python-version: "3.13t"
             flac: "system"
           - os: ubuntu-24.04-arm
-            python-version: "3.14"
+            python-version: "3.15"
             flac: "system"
 
     runs-on: ${{ matrix.os }}