chore(deps): update peaceiris/actions-mdbook action to v2 (#253)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/deploy-docs.yaml

@@ -16,7 +16,7 @@ jobs:
       - uses: mkroening/rust-toolchain-toml@main
 
       - name: Setup mdBook
-        uses: peaceiris/actions-mdbook@v1
+        uses: peaceiris/actions-mdbook@v2
         with:
           mdbook-version: '0.4.36'