Add GitHub workflows.

Author: tatsy

.github/workflows/build.yml

@@ -0,0 +1,47 @@
+name: Build (CPU)
+on:
+  push:
+    branches: [master, dev]
+  # release:
+  #   types: [published]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        os:
+          - ubuntu-latest
+          - windows-latest
+          - macos-latest
+        version:
+          - "3.9"
+          - "3.10"
+          - "3.11"
+          - "3.12"
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Check out repository code
+        uses: actions/checkout@v4
+      - name: Install Poetry
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install poetry
+      - name: Setup Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.version }}
+          cache: "poetry"
+      - name: Install dependencies
+        run: |
+          poetry install
+      - name: Build
+        run: |
+          poetry install
+      # - name: Check
+      #   run: poetry run python -c "import cshogi"
+      # - name: Publish
+      #   if: github.event_name == 'release' && github.event.action == 'published'
+      #   env:
+      #     TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
+      #     TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}
+      #   run: twine upload dist/*

README.md

@@ -1,6 +1,8 @@
 torchmcubes: marching cubes for PyTorch
 ===
 
+[![Build (CPU)](https://github.com/tatsy/torchmcubes/actions/workflows/build.yml/badge.svg?branch=master)](https://github.com/tatsy/torchmcubes/actions/workflows/build.yml)
+
 > Marching cubes for PyTorch environment. Backend is implemented with C++ and CUDA.
 
 ## Install