Grape::Middleware::Versioner::Header doesn't work for vendor strings with underscores

Upgrading to Grape >= 0.14.0 crashes our some of our requests.

undefined method `[]' for nil:NilClass
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/versioner/header.rb:181:in `request_vendor'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/versioner/header.rb:123:in `block in headers_contain_wrong_vendor?'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/versioner/header.rb:122:in `each'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/versioner/header.rb:122:in `all?'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/versioner/header.rb:122:in `headers_contain_wrong_vendor?'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/versioner/header.rb:37:in `before'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/base.rb:29:in `call!'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/base.rb:24:in `call'
~/.rvm/gems/ruby-2.3.7/gems/warden-1.2.7/lib/warden/manager.rb:32:in `call'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/error.rb:37:in `block in call!'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/error.rb:36:in `catch'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/error.rb:36:in `call!'
~/.rvm/gems/ruby-2.3.7/gems/grape-1.0.3/lib/grape/middleware/base.rb:24:in `call'
~/.rvm/gems/ruby-2.3.7/gems/rack-2.0.5/lib/rack/head.rb:12:in `call'

The issue seems related to the Regex that captures the vendor within Middleware Versioner Headers.
Our application uses a Warden middleware, which is raising this exception.

VENDOR_VERSION_HEADER_REGEX = /\Avnd\.([a-z0-9.\-_!#\$&\^]+?)(?:-([a-z0-9*.]+))?(?:\+([a-z0-9*\-.]+))?\z/

The Middleware raises an exception caused by the Regex not matching.

# https://github.com/ruby-grape/grape/blob/v0.14.0/lib/grape/middleware/versioner/header.rb#L181
subtype.match(VENDOR_VERSION_HEADER_REGEX)[1]

Any suggestion would be appreciated.

Edit

Unfortunately some of our requests used underscores in the format, which would lead to the chain of lazy matching breaking and making everything unmatched (i.e. vendor).

vnd.mycompany-v1.custom_format

Start in lib/grape/middleware/versioner/header.rb at request_vendor and VENDOR_VERSION_HEADER_REGEX. Reproduce the failure with the vendor string vnd.mycompany-v1.custom_format and inspect why the match becomes nil. Done means vendor strings containing underscores no longer raise an exception and are parsed correctly.