我正在尝试将一个大型Django项目部署到heroku。我安装了Heroku CLI，登录，创建了一个应用程序并运行：

git push heroku master

我已经设置了一个Pipfile和requirements.txt。我添加了runtime.txt以指定需要python 2.7。这也在Pipfile中。这是我从推送到heroku得到的结果：

$ git push heroku master
Counting objects: 12159, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (4853/4853), done.
Writing objects: 100% (12159/12159), 20.94 MiB | 1.82 MiB/s, done.
Total 12159 (delta 6859), reused 12036 (delta 6751)
remote: Compressing source files... done.
remote: Building source:
remote: 
remote: -----> Python app detected
remote: -----> Installing python-3.6.4
remote: -----> Installing pip
remote: -----> Installing dependencies with Pipenv 11.8.2…
remote:        Your Pipfile.lock (3b2ba9) is out of date. Expected: (83a5b4).
remote:        Aborting deploy.
remote:  !     Push rejected, failed to compile Python app.
remote: 
remote:  !     Push failed
remote: Verifying deploy....
remote: 
remote: !   Push rejected to camp-infinity.
remote: 
To https://git.heroku.com/camp-infinity.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/camp-infinity.git'

由于某种原因，它尝试安装python 3，而且它也不喜欢我的Pipfile.lock文件。我试着删除它，并使用pipenv install再次生成它，但是没有任何改变。