Add Python 3.14 classifier. (#11793)

Author: trivialfis

ops/script/pypi_variants.py

@@ -76,7 +76,9 @@ def make_pyproject(
         NCCL, NCCL_WHL.format(require_nccl_dep) if require_nccl_dep != "na" else ""
     )
     pyproject = (
-        f"# Generated by `{os.path.basename(__file__)}`, don't edit.\n" + pyproject
+        f"# Generated by `{os.path.basename(__file__)}`, don't edit: "
+        f"'--use-suffix={use_suffix} --require-nccl-dep={require_nccl_dep} "
+        f"--create-stub={create_stub}'\n" + pyproject
     )
 
     with open(OUT_PATH, "w") as fd:
@@ -90,7 +92,10 @@ def make_pyproject(
         type=str,
         choices=["na", "cpu"] + CUDA_VARIANTS,
         default="na",
-        help="When using this option, rename the package name to xgboost-[suffix]. Set to 'na' to disable",
+        help=(
+            "When using this option, rename the package name to xgboost-[suffix]. "
+            "Set to 'na' to disable"
+        ),
     )
     parser.add_argument(
         "--require-nccl-dep",

python-package/pyproject.toml

@@ -1,4 +1,4 @@
-# Generated by `pypi_variants.py`, don't edit.
+# Generated by `pypi_variants.py`, don't edit: '--use-suffix=na --require-nccl-dep=cu12 --create-stub=False'
 [build-system]
 requires = [
     "hatchling>=1.12.1",
@@ -29,6 +29,7 @@ classifiers = [
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
 ]
 dependencies = [
     "numpy",

python-package/pyproject.toml.in

@@ -28,6 +28,7 @@ classifiers = [
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
 ]
 dependencies = [
     "numpy",