Upgrade GitHub Pages workflow to pnpm 8

Author: skirtles-code

.github/workflows/pages.yml

@@ -33,7 +33,7 @@ jobs:
       - name: Install pnpm
         uses: pnpm/action-setup@v2
         with:
-          version: 7
+          version: 8
       - name: Set up Node
         uses: actions/setup-node@v3
         with: