Dmytro Shteflyuk

There are several related issues: 1. `daemon/daemon_helper.rb` requires mongrel to be installed system wide, but then it starts server, which uses Bundler, and there is no mongrel in Gemfile. So...

Added support for .tool-versions file in Gemfile for Ruby projects

8

_This MR is related to https://github.com/dependabot/dependabot-core/issues/1033 in a way that it adds support for `.tool-versions` files for Ruby projects._ Starting with Bunder 2.4.20, it supports specifying Ruby version via `.tool-versions`...