ci: migrate pages workflow from npm to bun

Author: involvex

.github/workflows/pages.yml

@@ -32,14 +32,14 @@ jobs:
           fetch-depth: 0
           persist-credentials: false
 
-      - name: Setup Node.js
-        uses: actions/setup-node@v4
-        with:
-          node-version: "20"
-          cache: "npm"
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v1
+
+      - name: Install dependencies
+        run: bun install
 
       - name: Install conventional-changelog-cli
-        run: npm install -g conventional-changelog-cli
+        run: bun install -g conventional-changelog-cli
 
       - name: Generate changelog
         id: changelog