feat: add npm publishing to release workflow

Automatically publish @invoicetronic/sdk to npm when GitHub releases are created.

Author: nicolaiarocci

.github/workflows/release.yml

@@ -1,4 +1,4 @@
-name: Create Release
+name: Create Release and Publish to NPM
 
 on:
   push:
@@ -22,3 +22,32 @@ jobs:
           make_latest: true
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  npm-publish:
+    needs: github-release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '18'
+          registry-url: 'https://registry.npmjs.org'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build package
+        run: npm run build
+
+      - name: Update package version
+        run: |
+          TAG_VERSION=${GITHUB_REF#refs/tags/v}
+          npm version $TAG_VERSION --no-git-tag-version
+
+      - name: Publish to NPM
+        run: npm publish --access public
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}