update ruby version and replace bank-contact with iban-tools

.ruby-version

@@ -1 +1 @@
-3.0.2
+3.4.3

Gemfile.lock

@@ -2,27 +2,27 @@ PATH
   remote: .
   specs:
     girocode (0.2.0)
-      bank-contact
+      iban-tools
       rqrcode
 
 GEM
   remote: https://rubygems.org/
   specs:
-    bank-contact (0.0.6)
     chunky_png (1.4.0)
-    docile (1.4.0)
-    minitest (5.14.4)
-    rake (13.0.6)
-    rqrcode (2.1.0)
+    docile (1.4.1)
+    iban-tools (1.2.1)
+    minitest (5.25.5)
+    rake (13.3.0)
+    rqrcode (3.1.0)
       chunky_png (~> 1.0)
-      rqrcode_core (~> 1.0)
-    rqrcode_core (1.2.0)
-    simplecov (0.21.2)
+      rqrcode_core (~> 2.0)
+    rqrcode_core (2.0.0)
+    simplecov (0.22.0)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
       simplecov_json_formatter (~> 0.1)
-    simplecov-html (0.12.3)
-    simplecov_json_formatter (0.1.3)
+    simplecov-html (0.13.1)
+    simplecov_json_formatter (0.1.4)
 
 PLATFORMS
   ruby
@@ -34,4 +34,4 @@ DEPENDENCIES
   simplecov
 
 BUNDLED WITH
-   2.2.22
+   2.6.8

girocode.gemspec

@@ -17,5 +17,5 @@ Gem::Specification.new do |s|
   s.require_paths = ['lib']
 
   s.add_dependency 'rqrcode'
-  s.add_dependency 'bank-contact'
+  s.add_dependency 'iban-tools'
 end

lib/girocode.rb

@@ -1,5 +1,5 @@
 require 'bigdecimal'
-require 'bank/contact'
+require 'iban-tools'
 require 'rqrcode'
 
 require_relative 'girocode/version'

lib/girocode/code.rb

@@ -23,10 +23,10 @@ module Girocode
     def bic=(value)
       if value.nil?
         @bic = nil
+      elsif value.match? /\A[A-Z0-9]{4}([A-Z]{2})([A-Z0-9]{2})([A-Z0-9]{3})?\z/
+        @bic = value
       else
-        bic = Bank::BIC.new(value)
-        raise ArgumentError, "Invalid BIC #{value.inspect}" unless bic.valid?
-        @bic = bic.to_s
+        raise ArgumentError, "Invalid BIC #{value.inspect}"
       end
     end
 
@@ -39,9 +39,9 @@ module Girocode
     end
 
     def iban=(value)
-      iban = Bank::IBAN.new(value)
-      raise ArgumentError, "Invalid IBAN #{value.inspect}" unless iban.valid?
-      @iban = iban.to_s
+      raise ArgumentError, "Invalid IBAN #{value.inspect}" unless IBANTools::IBAN.valid?(value)
+
+      @iban = value
     end
 
     def currency=(value)