Remove Ruby 2.4 from the test matrix
Remove Ruby 2.4 from the test matrix

Rails 6 will require Ruby 2.5 or newer. See rails/rails#34754.

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