build: initialize JavaScript Action project (#69)

* build: initialize JavaScript action project

* chore(dependabot): check for npm package updates

* style: ignore `main` dir and `README.md` from being formatted

* ci: add Build workflow that contains Build Package job

* ci: add Test Package job in the Test workflow

* test: add an empty `main.test.ts` test

* chore: adjust Git attributes for `main/index.mjs` file

* docs(readme): add a build status badge

.github/workflows/build.yaml

@@ -0,0 +1,39 @@
+name: Build
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches: [main]
+jobs:
+  build-package:
+    name: Build Package
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4.1.1
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4.0.0
+        with:
+          node-version: latest
+
+      - name: Update Yarn
+        run: corepack enable && yarn set version stable
+
+      - name: Cache deps
+        uses: actions/cache@v3.3.2
+        with:
+          path: .yarn
+          key: yarn-${{ runner.os }}-${{ hashFiles('yarn.lock') }}
+
+      - name: Install deps
+        run: yarn install
+
+      - name: Check lib
+        run: yarn check
+
+      - name: Bundle dist
+        run: yarn bundle
+
+      - name: Check diff
+        run: git diff --exit-code HEAD