Merge pull request #230 from rust-lang/nikomatsakis-patch-3

update name of branch

Author: nikomatsakis

.github/workflows/deploy.yml

@@ -14,7 +14,7 @@ jobs:
       - run: mdbook build
       - name: Deploy
         uses: peaceiris/actions-gh-pages@v3
-        if: ${{ github.ref == 'refs/heads/main' }}
+        if: ${{ github.ref == 'refs/heads/master' }}
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./book