Add 3.15 to CI (#678)

Author: clin1234

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       matrix:
         os: ["ubuntu-latest", "windows-latest", "windows-11-arm", "macos-latest"]
-        py: ["3.14", "3.14t", "3.13", "3.12", "3.11", "3.10"]
+        py: ["3.15", "3.15t", "3.14", "3.14t", "3.13", "3.12", "3.11", "3.10"]
         exclude:
           - os: windows-11-arm
             py: "3.10"