One does not simply merge into master

.github/workflows/build.yml

@@ -0,0 +1,59 @@
+name: build
+
+on:
+  release:
+    types: [created]
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+            output: confy-linux
+          - os: macos-latest
+            output: confy-macos
+          - os: windows-latest
+            output: confy-windows.exe
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: set up python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+
+      - name: install pyinstaller
+        run: pip install pyinstaller
+
+      - name: build
+        run: pyinstaller --onefile main.py --name ${{ matrix.output }}
+
+      - name: get release upload url
+        id: get_release
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const release = await github.rest.repos.getReleaseByTag({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              tag: context.ref.replace('refs/tags/', '')
+            });
+            return release.data.upload_url;
+          result-encoding: string
+
+      - name: upload binary
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.get_release.outputs.result }}
+          asset_path: dist/${{ matrix.output }}
+          asset_name: ${{ matrix.output }}
+          asset_content_type: application/octet-stream