Update required rspec version

bpo · bpo · commit 5976ee33de19 · 2020-03-05T11:51:04.000-08:00
Commit 693c2e9 introduced a dependency on `to_stderr_from_any_process`, an API introduced in rspec 3.2.
diff --git a/Gemfile b/Gemfile
@@ -10,7 +10,7 @@ end
 group :test do
   gem "childlabor"
   gem "coveralls", ">= 0.8.19"
-  gem "rspec", ">= 3"
+  gem "rspec", ">= 3.2"
   gem "rspec-mocks", ">= 3"
   gem "rubocop", "~> 0.50.0"
   gem "simplecov", ">= 0.13"
