CI: Validate on Python 3.15

.github/workflows/test.yaml

@@ -25,7 +25,8 @@ jobs:
           "3.12",
           "3.13",
           "3.14",
-          "3.14t",
+          "3.15",
+          "3.15t",
           "pypy3.11",
         ]
 

pyproject.toml

@@ -26,6 +26,7 @@ classifiers = [
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
   "Programming Language :: Python :: 3.14",
+  "Programming Language :: Python :: 3.15",
   "Programming Language :: Python :: Free Threading",
   "Programming Language :: Python :: Implementation :: CPython",
   "Programming Language :: Python :: Implementation :: PyPy",