Heroku build is failing

[inarie]

The Heroku build fails due to the package using ruby-2.6.6.

Log:

-----> Building on the Heroku-22 stack
-----> Determining which buildpack to use for this app
 !     Warning: Multiple default buildpacks reported the ability to handle this app. The first buildpack in the list below will be used.
			Detected buildpacks: Ruby,Node.js
			See https://devcenter.heroku.com/articles/buildpacks#buildpack-detect-order
-----> Ruby app detected
-----> Installing bundler 2.3.10
-----> Removing BUNDLED WITH version in the Gemfile.lock
-----> Compiling Ruby/Rails
       Command: 'set -o pipefail; curl -L --fail --retry 5 --retry-delay 1 --connect-timeout 3 --max-time 30 https://heroku-buildpack-ruby.s3.us-east-1.amazonaws.com/heroku-22/ruby-2.6.6.tgz -s -o - | tar zxf - ' failed on attempt 1 of 3.
       Command: 'set -o pipefail; curl -L --fail --retry 5 --retry-delay 1 --connect-timeout 3 --max-time 30 https://heroku-buildpack-ruby.s3.us-east-1.amazonaws.com/heroku-22/ruby-2.6.6.tgz -s -o - | tar zxf - ' failed on attempt 2 of 3.
 !
 !     The Ruby version you are trying to install does not exist on this stack.
 !     
 !     You are trying to install ruby-2.6.6 on heroku-22.
 !     
 !     Ruby ruby-2.6.6 is present on the following stacks:
 !     
 !     - heroku-18
 !     - heroku-20
 !     
 !     Heroku recommends you use the latest supported Ruby version listed here:
 !     https://devcenter.heroku.com/articles/ruby-support#supported-runtimes
 !     
 !     For more information on syntax for declaring a Ruby version see:
 !     https://devcenter.heroku.com/articles/ruby-versions
 !
 !     Push rejected, failed to compile Ruby app.
 !     Push failed