Merge pull request #247 from xopt-org/fix_pypi

Fix PyPI update to Python 3.9

.github/workflows/pypi_upload.yml

@@ -14,10 +14,10 @@ jobs:
       - uses: actions/checkout@v3
         with:
           fetch-depth: 0
-      - name: Set up Python 3.7
+      - name: Set up Python 3.9
         uses: actions/setup-python@v1
         with:
-          python-version: 3.7
+          python-version: 3.9
       - name: Install pypa/build
         run: >-
           python -m