add release workflow

.github/workflows/release.yml

@@ -0,0 +1,23 @@
+name: release
+
+# Only do the release on x.y.z tags.
+on:
+  push:
+    tags:
+    - "[0-9]+.[0-9]+.[0-9]+"
+
+jobs:
+  package:
+    name: Publish Rust package
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Set up Rust
+        uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          toolchain: stable
+      - name: Publish to crates.io
+        run: cargo publish
+        env:
+          CARGO_REGISTRY_TOKEN: ${{secrets.CARGO_REGISTRY_TOKEN}}