Include github action to publish when in master and new version defined (#6)

Author: jordivx

.github/workflows/publish.yml

@@ -0,0 +1,50 @@
+name: Publish to npm
+
+on:
+  push:
+    branches:
+      - master
+
+permissions:
+  contents: read
+  id-token: write  # Required for OIDC
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '24'
+          registry-url: 'https://registry.npmjs.org'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build library
+        run: npm run pack-lib
+
+      - name: Check if version exists
+        id: check_version
+        run: |
+          PACKAGE_NAME=$(node -p "require('./package.json').name")
+          VERSION=$(node -p "require('./package.json').version")
+          echo "Checking if $PACKAGE_NAME@$VERSION exists..."
+          
+          if npm view "$PACKAGE_NAME@$VERSION" version &>/dev/null; then
+            echo "Version $VERSION already exists in registry"
+            echo "should_publish=false" >> $GITHUB_OUTPUT
+          else
+            echo "Version $VERSION does not exist, will publish"
+            echo "should_publish=true" >> $GITHUB_OUTPUT
+          fi
+        working-directory: ./dist/ngx-appshell
+
+      - name: Publish to npm
+        if: steps.check_version.outputs.should_publish == 'true'
+        run: npm publish --access public
+        working-directory: ./dist/ngx-appshell