Rely on COVERAGE_ONLY_ON (but only enforce minimum=100 on 3.1+)

Author: nevinera

script/rspec_with_simplecov

@@ -25,18 +25,17 @@ begin
   old_verbose, $VERBOSE = $VERBOSE, false
 
   skip_because_no_coverage = ENV['NO_COVERAGE']
-  skip_because_ruby_too_low = RUBY_VERSION.to_f < 2.1
   skip_because_wrong_version = ENV['COVERAGE_ONLY_ON'] && ENV['COVERAGE_ONLY_ON'].to_f != RUBY_VERSION.to_f
 
-  unless skip_because_no_coverage || skip_because_ruby_too_low || skip_because_wrong_version
+  unless skip_because_no_coverage || skip_because_wrong_version
     require 'simplecov'
 
     SimpleCov.start do
       root File.expand_path("../..", __FILE__)
       add_filter %r{/bundle/}
       add_filter %r{/tmp/}
       add_filter %r{/spec/}
-      minimum_coverage(100)
+      minimum_coverage(100) if RUBY_VERSION.to_f >= 3.1
     end
   end
 rescue LoadError # rubocop:disable Lint/SuppressedException