Upgrade `spring` to `2.1.1`

The `bundler 2.1.4` and `ruby 2.7`
do require a new spring version
due to how gems are being resolved.

Gemfile

@@ -367,7 +367,7 @@ group :development, :test do
   # Generate Fake data
   gem 'ffaker', '~> 2.10'
 
-  gem 'spring', '~> 2.0.0'
+  gem 'spring', '~> 2.1.0'
   gem 'spring-commands-rspec', '~> 1.0.4'
 
   gem 'gitlab-styles', '~> 5.0.0', require: false

Gemfile.lock

@@ -1122,8 +1122,7 @@ GEM
     slack-messenger (2.3.4)
     snowplow-tracker (0.6.1)
       contracts (~> 0.7, <= 0.11)
-    spring (2.0.2)
-      activesupport (>= 4.2)
+    spring (2.1.1)
     spring-commands-rspec (1.0.4)
       spring (>= 0.9.1)
     sprockets (3.7.2)
@@ -1179,7 +1178,7 @@ GEM
     truncato (0.7.11)
       htmlentities (~> 4.3.1)
       nokogiri (>= 1.7.0, <= 2.0)
-    tzinfo (1.2.7)
+    tzinfo (1.2.8)
       thread_safe (~> 0.1)
     u2f (0.2.1)
     uber (0.1.0)
@@ -1498,7 +1497,7 @@ DEPENDENCIES
   simplecov-cobertura (~> 1.3.1)
   slack-messenger (~> 2.3.4)
   snowplow-tracker (~> 0.6.1)
-  spring (~> 2.0.0)
+  spring (~> 2.1.0)
   spring-commands-rspec (~> 1.0.4)
   sprockets (~> 3.7.0)
   sshkey (~> 2.0)

bin/spring

 #!/usr/bin/env ruby
 
-# This file loads spring without using Bundler, in order to be fast.
+# This file loads Spring without using Bundler, in order to be fast.
 # It gets overwritten when you run the `spring binstub` command.
 
 unless (defined?(Spring) || ENV['ENABLE_SPRING'] != '1') && File.basename($0) != 'spring'
   require 'rubygems'
   require 'bundler'
 
-  if (match = Bundler.default_lockfile.read.match(/^GEM$.*?^    (?:  )*spring \((.*?)\)$.*?^$/m))
-    Gem.paths = { 'GEM_PATH' => [Bundler.bundle_path.to_s, *Gem.path].uniq.join(Gem.path_separator) }
-    gem 'spring', match[1]
+  lockfile = Bundler::LockfileParser.new(Bundler.default_lockfile.read)
+  spring = lockfile.specs.detect { |spec| spec.name == 'spring' }
+  if spring
+    Gem.use_paths Gem.dir, Bundler.bundle_path.to_s, *Gem.path
+    gem 'spring', spring.version
     require 'spring/binstub'
   end
 end