Fully remove duplicated upgrade information [ci skip]
Fully remove duplicated upgrade information [ci skip]

On #34261 we removed the whole upgrade section. This warning is also
included in the Upgrade guides [here](https://github.com/rails/rails/blame/master/guides/source/upgrading_ruby_on_rails.md#L1390)
and should also be removed.

rafaelfranca/omg-rails,Erol/rails,tgxworld/rails,betesh/rails,flanger001/rails,lcreid/rails,palkan/rails,kddeisz/rails,notapatch/rails,starknx/rails,Stellenticket/rails,flanger001/rails,utilum/rails,arunagw/rails,Envek/rails,Erol/rails,rails/rails,shioyama/rails,BlakeWilliams/rails,notapatch/rails,flanger001/rails,schuetzm/rails,rafaelfranca/omg-rails,utilum/rails,vipulnsward/rails,Vasfed/rails,fabianoleittes/rails,Envek/rails,Erol/rails,notapatch/rails,yahonda/rails,Vasfed/rails,rafaelfranca/omg-rails,Stellenticket/rails,tjschuck/rails,kmcphillips/rails,georgeclaghorn/rails,kmcphillips/rails,esparta/rails,tjschuck/rails,Edouard-chin/rails,iainbeeston/rails,arunagw/rails,Vasfed/rails,georgeclaghorn/rails,mechanicles/rails,repinel/rails,kmcphillips/rails,joonyou/rails,joonyou/rails,MSP-Greg/rails,yahonda/rails,EmmaB/rails-1,shioyama/rails,mechanicles/rails,fabianoleittes/rails,BlakeWilliams/rails,palkan/rails,yahonda/rails,tgxworld/rails,yhirano55/rails,Stellenticket/rails,betesh/rails,yalab/rails,yalab/rails,tgxworld/rails,eileencodes/rails,BlakeWilliams/rails,tjschuck/rails,BlakeWilliams/rails,iainbeeston/rails,lcreid/rails,esparta/rails,yalab/rails,fabianoleittes/rails,fabianoleittes/rails,schuetzm/rails,flanger001/rails,yawboakye/rails,esparta/rails,iainbeeston/rails,vipulnsward/rails,utilum/rails,bogdanvlviv/rails,bogdanvlviv/rails,repinel/rails,palkan/rails,eileencodes/rails,joonyou/rails,tjschuck/rails,tgxworld/rails,jeremy/rails,yahonda/rails,MSP-Greg/rails,Edouard-chin/rails,prathamesh-sonpatki/rails,kddeisz/rails,rails/rails,bogdanvlviv/rails,lcreid/rails,arunagw/rails,Envek/rails,gauravtiwari/rails,kddeisz/rails,shioyama/rails,betesh/rails,EmmaB/rails-1,rails/rails,vipulnsward/rails,MSP-Greg/rails,bogdanvlviv/rails,yhirano55/rails,iainbeeston/rails,rails/rails,mechanicles/rails,betesh/rails,prathamesh-sonpatki/rails,jeremy/rails,gauravtiwari/rails,repinel/rails,MSP-Greg/rails,schuetzm/rails,Stellenticket/rails,Edouard-chin/rails,yawboakye/rails,yalab/rails,prathamesh-sonpatki/rails,starknx/rails,repinel/rails,EmmaB/rails-1,Erol/rails,palkan/rails,utilum/rails,georgeclaghorn/rails,kddeisz/rails,yhirano55/rails,esparta/rails,yawboakye/rails,georgeclaghorn/rails,schuetzm/rails,Edouard-chin/rails,jeremy/rails,gauravtiwari/rails,vipulnsward/rails,mechanicles/rails,Vasfed/rails,yawboakye/rails,notapatch/rails,jeremy/rails,joonyou/rails,eileencodes/rails,Envek/rails,prathamesh-sonpatki/rails,lcreid/rails,arunagw/rails,shioyama/rails,starknx/rails,yhirano55/rails,kmcphillips/rails,eileencodes/rails