chore: publish new releases using GH actions

.github/workflows/release-please.yml

@@ -18,3 +18,20 @@ jobs:
           release-type: node
           package-name: unchained-wallets
           command: manifest
+
+      # The logic below handles the npm publication:
+      - uses: actions/checkout@v2
+        # 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 }}