[DO NOT MERGE] Temporarily force PR builds to test 3.15/3.15t on Linux

PR builds normally limit to python_versions[0] (3.10); override that to
["3.15", "3.15t"] for linux and linux-aarch64 so this PR's CI actually
exercises the new versions (macOS/Windows keep 3.10 to avoid an empty
matrix). Revert this commit before merging.

Author: atalman

tools/scripts/generate_binary_build_matrix.py

@@ -456,7 +456,13 @@ def generate_wheels_matrix(
             arches += [XPU]
 
     if limit_pr_builds:
-        python_versions = [python_versions[0]]
+        # TEMPORARY (DO NOT MERGE): force PR builds to exercise 3.15 / 3.15t on
+        # Linux so this PR's CI validates the new versions. Revert to
+        # `python_versions = [python_versions[0]]` before merging.
+        if os in (LINUX, LINUX_AARCH64):
+            python_versions = ["3.15", "3.15t"]
+        else:
+            python_versions = [python_versions[0]]
 
     global WHEEL_CONTAINER_IMAGES