Remove unused dependencies bigdecimal and activesupport

Gemfile.lock

@@ -2,8 +2,6 @@ PATH
   remote: .
   specs:
     fastlane-plugin-wpmreleasetoolkit (8.1.0)
-      activesupport (>= 6.1.7.1)
-      bigdecimal (~> 1.4)
       buildkit (~> 1.5)
       chroma (= 0.2.0)
       diffy (~> 3.3)
@@ -53,7 +51,6 @@ GEM
     aws-sigv4 (1.5.2)
       aws-eventstream (~> 1, >= 1.0.2)
     babosa (1.0.4)
-    bigdecimal (1.4.4)
     buildkit (1.5.0)
       sawyer (>= 0.6)
     buildkite-test_collector (2.3.1)

fastlane-plugin-wpmreleasetoolkit.gemspec

@@ -24,7 +24,6 @@ Gem::Specification.new do |spec|
   # since this would cause a circular dependency
 
   # spec.add_dependency 'your-dependency', '~> 1.0.0'
-  spec.add_dependency 'activesupport', '>= 6.1.7.1'
   spec.add_dependency 'buildkit', '~> 1.5'
   spec.add_dependency 'chroma', '0.2.0'
   spec.add_dependency 'diffy', '~> 3.3'
@@ -41,13 +40,6 @@ 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'
 
-  # Some of the upstream code uses `BigDecimal.new` which version 2.0 of the
-  # `bigdecimal` gem removed. Until we'll find the time to identify the
-  # dependencies and see if we can move them to something compatible with
-  # modern `bigdecimal`, let's constrain the gem to a version still supporting
-  # `.new` but which warns about it deprecation.
-  spec.add_dependency 'bigdecimal', '~> 1.4'
-
   spec.add_development_dependency 'bundler', '~> 2.0'
   spec.add_development_dependency 'cocoapods', '~> 1.10'
   # Use at least Fastlane 2.210.0 to ensure compatibility with the Xcode 14 toolchain