[rubygems/rubygems] Fix test task name on generated readme when using test-unit
https://github.com/rubygems/rubygems/commit/2a24708a63
[rubygems/rubygems] Fix test task name on generated readme when using test-unit
test_task value to get the correct test task name ("test", not "test-unit").
names for each test frameworks.
https://github.com/rubygems/rubygems/commit/2a24708a63