automatic builds on github actions.

.github/workflows/release.yml

@@ -0,0 +1,37 @@
+name: build for all platforms
+
+on:
+  push:
+    tags:
+      - '*'
+
+permissions:
+  contents: write
+
+jobs:
+  make-release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/create-release@latest
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref }}
+          release_name: ${{ github.ref }}
+  build-all-for-all:
+    runs-on: ubuntu-latest
+    needs:
+      - make-release
+    strategy:
+      matrix:
+        goos: [linux, freebsd]
+        goarch: [amd64]
+    steps:
+      - uses: actions/checkout@v3
+      - uses: wangyoucao577/go-release-action@v1.30
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          goos: ${{ matrix.goos }}
+          goarch: ${{ matrix.goarch }}
+          goversion: "1.18"
+          overwrite: true