added GitHub workflow to publish to NPM's public registry

Author: Tyson Williams

.github/workflows/npm-publish.yml

@@ -0,0 +1,27 @@
+# Based on template copied from https://github.com/marketplace/actions/publish-to-npm#usage
+name: npm-publish
+on:
+  push:
+    branches:
+      - master
+jobs:
+  npm-publish:
+    name: npm-publish
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@master
+    - name: Set up Node.js
+      uses: actions/setup-node@master
+      with:
+        node-version: 12.0.0
+    - name: Publish if version has been updated
+      uses: pascalgn/npm-publish-action@1.3.3
+      with: # Documentation of inputs https://github.com/marketplace/actions/publish-to-npm#inputs
+        tag_name: "v%s"
+        tag_message: "v%s"
+        commit_pattern: "^Release (\\S+)"
+        workspace: ".codedoc"
+      env: # Documentation of environment variables https://github.com/marketplace/actions/publish-to-npm#environment-variables
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # Leave this as is, it's automatically generated
+        NPM_AUTH_TOKEN: ${{ secrets.NPM_AUTH_TOKEN }} # Must be set in repo settings