Add CI workflow to check project packaging is up to date

On every push and pull request that affects relevant files, check to make sure the ncc packaging is up to date.

Author: per1234

.github/workflows/check-packaging-ncc-typescript-npm.yml

@@ -0,0 +1,53 @@
+name: Check Packaging
+
+env:
+  # See: https://github.com/actions/setup-node/#readme
+  NODE_VERSION: 10.x
+
+on:
+  push:
+    paths:
+      - ".github/workflows/check-packaging-ncc-typescript-npm.yml"
+      - "lerna.json"
+      - "package.json"
+      - "package-lock.json"
+      - "Taskfile.ya?ml"
+      - "tsconfig.json"
+      - "**.[jt]sx?"
+  pull_request:
+    paths:
+      - ".github/workflows/check-packaging-ncc-typescript-npm.yml"
+      - "lerna.json"
+      - "package.json"
+      - "package-lock.json"
+      - "Taskfile.ya?ml"
+      - "tsconfig.json"
+      - "**.[jt]sx?"
+  workflow_dispatch:
+  repository_dispatch:
+
+jobs:
+  check-packaging:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v2
+        with:
+          node-version: ${{ env.NODE_VERSION }}
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Build project
+        run: |
+          npm run-script build
+          npm run-script pack
+
+      - name: Check packaging
+        # Ignoring CR because ncc's output has a mixture of line endings, while the repository should only contain
+        # Unix-style EOL.
+        run: git diff --ignore-cr-at-eol --color --exit-code dist

README.md

@@ -2,6 +2,7 @@
 
 [![Tests Status](https://github.com/arduino/arduino-lint-action/workflows/Test%20Action/badge.svg)](https://github.com/arduino/arduino-lint-action/actions?workflow=Test+Action)
 [![Integration Tests Status](https://github.com/arduino/arduino-lint-action/workflows/Integration%20Tests/badge.svg)](https://github.com/arduino/arduino-lint-action/actions?workflow=Integration+Tests)
+[![Check Packaging status](https://github.com/arduino/arduino-lint-action/actions/workflows/check-packaging-ncc-typescript-npm.yml/badge.svg)](https://github.com/arduino/arduino-lint-action/actions/workflows/check-packaging-ncc-typescript-npm.yml)
 [![Spellcheck Status](https://github.com/arduino/arduino-lint-action/workflows/Spell%20Check/badge.svg)](https://github.com/arduino/arduino-lint-action/actions?workflow=Spell+Check)
 
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