```ruby
require File.expand_path('../lib/dry/container/version', __FILE__)

Gem::Specification.new do |spec|
  spec.name          = 'dry-container'
  spec.version       = ::Dry::Container::VERSION
  spec.authors       = ['Andy Holland']
  spec.email         = ['andyholland1991@aol.com']
  spec.summary       = 'A simple, configurable object container implemented in Ruby'
  spec.homepage      = 'https://github.com/dry-rb/dry-container'
  spec.license       = 'MIT'

  spec.files         = `git ls-files -z`.split("\x0")
  spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
  spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
  spec.require_paths = ['lib']

  spec.required_ruby_version = '>= 2.3.0'

  spec.add_runtime_dependency 'concurrent-ruby', '~> 1.0'
  spec.add_runtime_dependency 'dry-configurable', '~> 0.1', '>= 0.1.3'

  spec.add_development_dependency 'bundler'
  spec.add_development_dependency 'rake'
  spec.add_development_dependency 'rspec'
end
```

Set bundler version in the gemspec
user
```ruby
require File.expand_path('../lib/dry/container/version', __FILE__)

Gem::Specification.new do |spec|
  spec.name          = 'dry-container'
  spec.version       = ::Dry::Container::VERSION
  spec.authors       = ['Andy Holland']
  spec.email         = ['andyholland1991@aol.com']
  spec.summary       = 'A simple, configurable object container implemented in Ruby'
  spec.homepage      = 'https://github.com/dry-rb/dry-container'
  spec.license       = 'MIT'

  spec.files         = `git ls-files -z`.split("\x0")
  spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
  spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
  spec.require_paths = ['lib']

  spec.required_ruby_version = '>= 2.3.0'

  spec.add_runtime_dependency 'concurrent-ruby', '~> 1.0'
  spec.add_runtime_dependency 'dry-configurable', '~> 0.1', '>= 0.1.3'

  spec.add_development_dependency 'bundler', '~> 2.1'
  spec.add_development_dependency 'rake'
  spec.add_development_dependency 'rspec'
end
```
assistant