Add bigdecimal as explicit dependency for Ruby 3.4+

Author: vnovitskyi

Gemfile.lock

@@ -2,12 +2,14 @@ PATH
   remote: .
   specs:
     ofx (0.4.4)
+      bigdecimal
       nokogiri (>= 1.16.3)
 
 GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.3)
+    bigdecimal (4.1.2)
     byebug (11.1.3)
     diff-lcs (1.5.1)
     json (2.19.4)

ofx.gemspec

@@ -26,6 +26,7 @@ Gem::Specification.new do |s|
 
   s.required_ruby_version = ">= 3.0.0"
 
+  s.add_dependency 'bigdecimal'
   s.add_dependency 'nokogiri', '>= 1.16.3'
   s.add_development_dependency 'byebug', '~> 11.1.3'
   s.add_development_dependency 'rake', '~> 13.2.1'