remove version requirement from bundler, causing problems with travis

Author: danmurphy1217

notion.gemspec

@@ -32,7 +32,7 @@ Gem::Specification.new do |spec|
     spec.add_runtime_dependency('httparty', '~> 0.17')
     spec.add_runtime_dependency('json', '~> 2.2')
 
-    spec.add_development_dependency("bundler", "~> 2.2.0")
+    spec.add_development_dependency("bundler")
     spec.add_development_dependency("rake", "~> 13.0.0")
     spec.add_development_dependency("rspec", "~> 3.9.0")
     spec.add_development_dependency("rubocop", "~> 1.4.0")