Bump rails from 6.0.4.8 to 6.0.6

[eitoball]

ChangeLogs

Checks changes since 6.0.4.8.

• [x] actioncable
  • Not used.
• [x] actionmailbox
  • Not used.
• [x] actionmailer
  • No changes.
• [x] actionpack
  • No changes.
• [x] actiontext
  • Not used.
• [x] actionview
  • No changes.
• [x] activejob
  • Not used.
• [x] activemodel
  • No changes.
• [x] activerecord
  • Change ActiveRecord::Coders::YAMLColumn default to safe_load
• [x] activestorage
  • No changes.
• [x] activesupport
  • No changes.
• [x] railties
  • No changes.