Merge pull request #2 from tessi/dependabot/bundler/bundler-tw-2.1

Update bundler requirement from ~> 1.17 to ~> 2.1

Author: tessi

malloc_trim.gemspec

@@ -24,7 +24,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
   spec.extensions    = ["ext/malloc_trim/extconf.rb"]
 
-  spec.add_development_dependency "bundler", "~> 1.17"
+  spec.add_development_dependency "bundler", "~> 2.1"
   spec.add_development_dependency "rake", "~> 13.0"
   spec.add_development_dependency "rake-compiler"
   spec.add_development_dependency "rspec", "~> 3.0"