我按照文档在gh-pages上部署了vue应用程序，但是遇到了错误。这是我在官方文档Stylus中提到的deploy.sh：
#!/usr/bin/env sh
# abort on errors
set -e
# build
npm run build
# navigate into the build output directory
cd dist
# if you are deploying to a custom domain
# echo 'www.example.com' > CNAME
git init
git add -A
git commit -m 'deploy'
# if you are deploying to https://<USERNAME>.github.io
# git push -f git@github.com:<USERNAME>/<USERNAME>.github.io.git master
# if you are deploying to https://<USERNAME>.github.io/<REPO>
git push -f git@github.com:VishalGulati/vue-grid-poc.git master:gh-pages
cd -
这是我遇到的错误：
git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
PS-我在分支gh-pages上运行了deploy.sh。我的应用是使用vue-cli 4的buit。
出什么问题了？