When I create a new rails app and deploy this, I get an error.
```===> ANALYZING
===> DETECTING
heroku/ruby 0.1.3
heroku/procfile 1.0.1
===> RESTORING
===> BUILDING
----> Installing bundler 2.2.21
----> Removing BUNDLED WITH version in the Gemfile.lock
----> Compiling Ruby/Rails
----> Using Ruby version: ruby-2.7.2
----> Loading Bundler Cache
----> Installing dependencies using bundler 2.2.21
Running: BUNDLE_WITHOUT='development:test' BUNDLE_PATH=/layers/heroku_ruby/gems/vendor/bundle BUNDLE_BIN=vendor/bundle/bin BUNDLE_DEPLOYMENT=1 bundle install -j4
Your Ruby version is 2.7.2, but your Gemfile specified 2.7.4
Bundler Output: Your Ruby version is 2.7.2, but your Gemfile specified 2.7.4
!
! Failed to install gems via Bundler.
! Detected a mismatch between your Ruby version installed and
! Ruby version specified in Gemfile or Gemfile.lock. You can
! correct this by running:
!
! $ bundle update --ruby
! $ git add Gemfile.lock
! $ git commit -m "update ruby version"
!
! If this does not solve the issue please see this documentation:
!
!
ERROR: failed to build: exit status 1
ERROR: failed to build: executing lifecycle: failed with status code: 51```