Add automated release process

Author: adamchainz

.github/workflows/build.yml

@@ -4,6 +4,8 @@ on:
   push:
     branches:
     - main
+    tags:
+    - '**'
   pull_request:
 
 concurrency:
@@ -90,3 +92,72 @@ jobs:
         with:
           name: html-report
           path: htmlcov
+
+  build:
+    name: Build wheels on ${{ matrix.os }}
+    if: >
+      startsWith(github.ref, 'refs/tags/') ||
+      github.ref == 'refs/heads/main' ||
+      contains(github.event.pull_request.labels.*.name, 'Build')
+
+    strategy:
+      matrix:
+        os:
+        - linux
+        - macos
+        - windows
+
+    runs-on: ${{ (matrix.os == 'linux' && 'ubuntu-24.04') || (matrix.os == 'macos' && 'macos-14') || (matrix.os == 'windows' && 'windows-2022') || 'unknown' }}
+
+    env:
+      CIBW_ARCHS_LINUX: x86_64 i686 aarch64
+      CIBW_ARCHS_MACOS: x86_64 universal2
+      CIBW_ARCHS_WINDOWS: AMD64 x86 ARM64
+      CIBW_BUILD: "cp39-* cp310-* cp311-* cp312-* cp313-*"
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: astral-sh/setup-uv@v3
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+        if: matrix.os == 'linux'
+        with:
+          platforms: all
+
+      - name: Build sdist
+        if: ${{ matrix.os == 'linux' }}
+        run: uv build --sdist
+
+      - name: Build wheels
+        run: uvx --from cibuildwheel==2.20.0 cibuildwheel --output-dir dist
+
+      - run: ${{ (matrix.os == 'windows' && 'dir') || 'ls -lh' }} dist/
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: dist-${{ matrix.os }}
+          path: dist
+
+  release:
+      needs: [coverage, build]
+      if: success() && startsWith(github.ref, 'refs/tags/')
+      runs-on: ubuntu-24.04
+      environment: release
+
+      permissions:
+        contents: read
+        id-token: write
+
+      steps:
+        - uses: actions/checkout@v4
+
+        - name: get dist artifacts
+          uses: actions/download-artifact@v4
+          with:
+            merge-multiple: true
+            pattern: dist-*
+            path: dist
+
+        - uses: pypa/gh-action-pypi-publish@release/v1