Update workflow to use bun instead of pnpm

.github/workflows/check.yaml

@@ -11,19 +11,16 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
-      - uses: pnpm/action-setup@v2
-        with:
-          version: 8
+      - uses: oven-sh/setup-bun@v1
       - uses: actions/setup-node@v3
         with:
           node-version: 20.x
-          cache: "pnpm"
 
       - name: Install dependencies
-        run: pnpm install --frozen-lockfile
+        run: bun install
 
       - name: Type check and lint
-        run: pnpm run typecheck && pnpm run lint
+        run: bun run typecheck && bun run lint
         env:
           # use dummy env variables to bypass t3-env check
           DATABASE_URL: mysql://test:xxxx@xxxxxxxxx:3306/test