Add npm publish workflow

.github/workflows/publish.yml

@@ -0,0 +1,50 @@
+on:
+  release:
+    types: [published]
+
+name: Publish to NPM
+
+jobs:
+  name: npm-publish
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Setup Node
+        uses: actions/setup-node@v1
+        with:
+          node-version: '14'
+
+      - name: 'Cache node_modules'
+        uses: actions/cache@v2
+        env:
+          cache-name: cache-node-modules
+        with:
+          # npm cache files are stored in `~/.npm` on Linux/macOS
+          path: |
+            **/node_modules
+            **/packages/**/node_modules
+          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/yarn.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-build-${{ env.cache-name }}-
+            ${{ runner.os }}-build-
+            ${{ runner.os }}-
+
+      - name: 'Yarn Install'
+        run: |
+          echo "//registry.npmjs.org/:_authToken=${{ secrets.NPM_TOKEN }}" > .npmrc
+          yarn install --frozen-lockfile
+      
+      - name: 'Build'
+        run: yarn build
+
+      - name: 'Test'
+        run: yarn test
+
+      - name: 'NPM Publish'
+        uses: JS-DevTools/npm-publish@v1
+        with:
+          token: ${{ secrets.NPM_TOKEN }}
+          access: "public"
+          check-version: true