build: add release workflow

.github/workflows/release.yml

@@ -0,0 +1,30 @@
+on:
+  push:
+    branches:
+      - main
+name: release
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: google-github-actions/release-please-action@v3
+        id: release
+        with:
+          release-type: node
+          package-name: purs-eval
+      # The logic below handles the npm publication:
+      - uses: actions/checkout@v3
+        # these if statements ensure that a publication only occurs when
+        # a new release is created:
+        if: ${{ steps.release.outputs.release_created }}
+      - uses: actions/setup-node@v3
+        with:
+          node-version: 18
+          registry-url: 'https://registry.npmjs.org'
+        if: ${{ steps.release.outputs.release_created }}
+      - run: npm ci
+        if: ${{ steps.release.outputs.release_created }}
+      - run: npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{secrets.NPM_TOKEN}}
+        if: ${{ steps.release.outputs.release_created }}