ci: add GitHub Actions pytest workflow for Python 3.11 and 3.12

Co-authored-by: zachessesjohnson <168567202+zachessesjohnson@users.noreply.github.com>

Author: Copilot

.github/workflows/pytest.yml

@@ -0,0 +1,34 @@
+name: pytest
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.11", "3.12"]
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install -U pip
+          if [ -f requirements.txt ]; then
+            pip install -r requirements.txt
+          else
+            pip install numpy pandas scipy statsmodels scikit-learn pytest
+          fi
+
+      - name: Run tests
+        run: |
+          pytest -q