Remove Bundler dependency and use Gemfile for dev

Removing the Bundler dependency definition allows us to use the latest
bundler version (4.x vs 2.x).

Additionally, it is no longer recommended to use the dev dependencies
API, it's best to use Gemfile instead. See
rubygems/bundler#7222

Author: mokagio

Gemfile

@@ -4,12 +4,23 @@ source('https://rubygems.org')
 
 gemspec
 
+# Only needed for specs (Time.use_zone, String#to_time, Hash#slice!)
+gem 'activesupport', '~> 8.1'
 gem 'buildkite-test_collector', '~> 2.3'
 gem 'codecov', require: false
 gem 'danger-dangermattic', '~> 1.0'
-gem 'webmock', require: false
-gem 'yard'
-
 # Security: https://github.com/lostisland/faraday/pull/1665
 # Faraday 2.0 is not compatible with Fastlane
 gem 'faraday', '~> 1.10', '>= 1.10.5'
+# Use at least Fastlane 2.210.0 to ensure compatibility with the Xcode 14 toolchain
+# See https://github.com/fastlane/fastlane/releases/tag/2.210.0
+gem 'fastlane', '~> 2.210'
+gem 'pry', '~> 0.12.2'
+gem 'rmagick', '~> 5.3'
+gem 'rspec', '~> 3.8'
+gem 'rspec_junit_formatter', '~> 0.4.1'
+gem 'rubocop', '~> 1.65'
+gem 'rubocop-rspec', '3.0'
+gem 'simplecov', '~> 0.16.1'
+gem 'webmock', require: false
+gem 'yard'

Gemfile.lock

@@ -436,7 +436,6 @@ PLATFORMS
 DEPENDENCIES
   activesupport (~> 8.1)
   buildkite-test_collector (~> 2.3)
-  bundler (~> 2.0)
   codecov
   danger-dangermattic (~> 1.0)
   faraday (~> 1.10, >= 1.10.5)
@@ -453,4 +452,4 @@ DEPENDENCIES
   yard
 
 BUNDLED WITH
-   2.7.2
+   4.0.14

fastlane-plugin-wpmreleasetoolkit.gemspec

@@ -45,18 +45,4 @@ Gem::Specification.new do |spec|
 
   # `google-cloud-storage` is required by fastlane, but we pin it in case it's not in the future
   spec.add_dependency 'google-cloud-storage', '~> 1.31'
-
-  # Only needed for specs (Time.use_zone, String#to_time, Hash#slice!)
-  spec.add_development_dependency 'activesupport', '~> 8.1'
-  spec.add_development_dependency 'bundler', '~> 2.0'
-  # Use at least Fastlane 2.210.0 to ensure compatibility with the Xcode 14 toolchain
-  # See https://github.com/fastlane/fastlane/releases/tag/2.210.0
-  spec.add_development_dependency 'fastlane', '~> 2.210'
-  spec.add_development_dependency 'pry', '~> 0.12.2'
-  spec.add_development_dependency 'rmagick', '~> 5.3'
-  spec.add_development_dependency 'rspec', '~> 3.8'
-  spec.add_development_dependency 'rspec_junit_formatter', '~> 0.4.1'
-  spec.add_development_dependency 'rubocop', '~> 1.65'
-  spec.add_development_dependency 'rubocop-rspec', '3.0'
-  spec.add_development_dependency 'simplecov', '~> 0.16.1'
 end