Set deploy-mdbook to v1.1

Author: XAMPPRocky

.github/workflows/deploy.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: XAMPPRocky/deploy-mdbook@master
+      - uses: XAMPPRocky/deploy-mdbook@v1.1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           build_only: ${{ github.ref != 'refs/heads/master' }}