ci: test Python 3.12 (#4059)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit


- **Chores**
- Updated the Python version in the CI/CD workflow from 3.11 to 3.12,
enhancing compatibility and performance for testing environments.
  
- **Bug Fixes**
- Improved error reporting in parallel training tests, providing clearer
output for failures to aid in debugging.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Jinzhe Zeng <jinzhe.zeng@rutgers.edu>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: njzjz

.github/workflows/test_python.yml

@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
       matrix:
         group: [1, 2, 3, 4, 5, 6]
-        python: ["3.8", "3.11"]
+        python: ["3.8", "3.12"]
 
     steps:
     - uses: actions/checkout@v4
@@ -68,7 +68,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ["3.8", "3.11"]
+        python: ["3.8", "3.12"]
     needs: testpython
     steps:
     - name: Get durations from cache

source/tests/tf/test_parallel_training.py

@@ -40,12 +40,16 @@ def test_two_workers(self):
             stdout=sp.PIPE,
             stderr=sp.STDOUT,
         )
+        lines = []
         for line in iter(popen.stdout.readline, b""):
             if hasattr(line, "decode"):
                 line = line.decode("utf-8")
             line = line.rstrip()
+            lines.append(line)
         popen.wait()
-        self.assertEqual(0, popen.returncode, "Parallel training failed!")
+        self.assertEqual(
+            0, popen.returncode, f"Parallel training failed!\n{''.join(lines)}"
+        )
 
 
 if __name__ == "__main__":