release on CI (#43)

* release on ci

* prepare for merge

.github/workflows/ci.yml

@@ -85,3 +85,21 @@ jobs:
         uses: re-actors/alls-green@release/v1
         with:
           jobs: ${{ toJSON(needs) }}
+
+  release:
+    needs: [check]
+    if: "success() && startsWith(github.ref, 'refs/tags/')"
+    runs-on: ubuntu-latest
+    environment: release
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: install rust stable
+      uses: dtolnay/rust-toolchain@stable
+
+    - uses: Swatinem/rust-cache@v2
+
+    - run: cargo publish
+      env:
+        CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}