modify python version for weekly test [skip-ci] (#550)

Fixes # .

### Description
This PR is used to update the weekly cpu test python version.
`valve_landmarks` bundle now requires python 3.9+ to use numpy 1.25.2

https://github.com/Project-MONAI/model-zoo/pull/542/files#diff-a11099ce2eebc4ce9f0721ca6674516e415d68d306ad76f1574fa0985973ff79R16
I temporarily modify yaml file to trigger the weekly test on this PR and
proves that the change works and will not impact other bundles.

https://github.com/Project-MONAI/model-zoo/actions/runs/7650854728


### Status
**Ready**

### Please ensure all the checkboxes:
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [x] Codeformat tests passed locally by running `./runtests.sh
--codeformat`.
- [ ] In-line docstrings updated.
- [ ] Update `version` and `changelog` in `metadata.json` if changing an
existing bundle.
- [ ] Please ensure the naming rules in config files meet our
requirements (please refer to: `CONTRIBUTING.md`).
- [ ] Ensure versions of packages such as `monai`, `pytorch` and `numpy`
are correct in `metadata.json`.
- [ ] Descriptions should be consistent with the content, such as
`eval_metrics` of the provided weights and TorchScript modules.
- [ ] Files larger than 25MB are excluded and replaced by providing
download links in `large_file.yml`.
- [ ] Avoid using path that contains personal information within config
files (such as use `/home/your_name/` for `"bundle_root"`).

---------

Signed-off-by: Yiheng Wang <[email protected]>

.github/workflows/weekly-tests-cpu.yml

@@ -12,10 +12,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Python 3.8
+    - name: Set up Python 3.9
       uses: actions/setup-python@v2
       with:
-        python-version: 3.8
+        python-version: 3.9
     - name: cache weekly timestamp
       id: pip-cache
       run: |
@@ -47,10 +47,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Python 3.8
+    - name: Set up Python 3.9
       uses: actions/setup-python@v2
       with:
-        python-version: 3.8
+        python-version: 3.9
     - name: cache weekly timestamp
       id: pip-cache
       run: |