Merge pull request #2805 from rspec/update-ci-build-scripts-2020-12-21-for-4-0-dev

Updates from rspec-dev (2020-12-21)

Author: JonRowe

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
     strategy:
       matrix:
         ruby:
-          - 3.0.0-preview2
+          - 3.0.0-rc1
           - 2.7
           - 2.6
           - 2.5

features/command_line/warnings_option.feature

@@ -7,7 +7,7 @@ Feature: `--warnings` option (run with warnings enabled)
       """ruby
       RSpec.describe do
         it 'generates warning' do
-          @undefined
+          $undefined
         end
       end
       """
@@ -19,7 +19,7 @@ Feature: `--warnings` option (run with warnings enabled)
       """ruby
       RSpec.describe do
         it 'generates warning' do
-          @undefined
+          $undefined
         end
       end
       """