add build-test workflow

.github/workflows/build-test.yaml

@@ -0,0 +1,25 @@
+name: Python package
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+  push:
+    branches: [master]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python
+        # This is the version of the action for setting up Python, not the Python version.
+        uses: actions/setup-python@v5
+        with:
+          # Semantic version range syntax or exact version of a Python version
+          python-version: "3.9"
+          # Optional - x64 or x86 architecture, defaults to x64
+          architecture: "x64"
+      # You can test your matrix by printing the current Python version
+      - name: Display Python version
+        run: python -c "import sys; print(sys.version)"