Include the shared context the new way.

lib/rspec/support/spec/with_isolated_directory.rb

@@ -1,9 +1,13 @@
 require 'tmpdir'
 
-RSpec.shared_context "isolated directory", :isolated_directory => true do
+RSpec.shared_context "isolated directory" do
   around do |ex|
     Dir.mktmpdir do |tmp_dir|
       Dir.chdir(tmp_dir, &ex)
     end
   end
 end
+
+RSpec.configure do |c|
+  c.include_context "isolated directory", :isolated_directory => true
+end