build: add workflow to check formatting on pull requests to main

Author: milan-codes

.github/workflows/check-formatting.yml

@@ -0,0 +1,14 @@
+name: Check formatting
+on:
+  pull_request:
+    branches: [main]
+jobs:
+  format:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: oven-sh/setup-bun@v2
+      - name: Install dependencies
+        run: bun install
+      - name: Check formatting
+        run: bun format:check

package.json

@@ -10,7 +10,8 @@
     "preview": "astro preview",
     "astro": "astro",
     "lint": "eslint .",
-    "format": "prettier . --write",
+    "format:write": "prettier . --write",
+    "format:check": "prettier . --check",
     "prepare": "husky"
   },
   "dependencies": {