Merge pull request #68 from rust-random/renovate/peaceiris-actions-mdbook-2.x

Update peaceiris/actions-mdbook action to v2

Author: dhardy

.github/workflows/gh-pages.yml

@@ -12,7 +12,7 @@ jobs:
       - uses: actions/checkout@v2
 
       - name: Setup mdBook
-        uses: peaceiris/actions-mdbook@v1
+        uses: peaceiris/actions-mdbook@v2
         with:
           mdbook-version: '0.4.4'
           # mdbook-version: 'latest'