I have been trying to deploy rails4 and ruby 2.6.5 version in to Heroku pipeline. It gives following error during release step.
Error Trace
Running release command...
bundler: failed to load command: rake (/app/vendor/bundle/ruby/2.6.0/bin/rake)
LoadError: library not found for class Digest::SHA1 -- digest/sha1
/app/vendor/ruby-2.6.5/lib/ruby/2.6.0/digest.rb:16:in `const_missing'
/app/vendor/ruby-2.6.5/lib/ruby/2.6.0/digest.rb:100:in `block in Digest'
/app/vendor/ruby-2.6.5/lib/ruby/2.6.0/digest.rb:98:in `synchronize'
/app/vendor/ruby-2.6.5/lib/ruby/2.6.0/digest.rb:98:in `Digest'
...........