Run CI on ruby 3.4 and ruby-head

- I've removed the TargetRubyVersion in rubocop.yml whith the hope it
will use the RubyVersion used in the CI test.
- Updated the minitestversion or it will fail with Ruby 3.5 when mutex_m
is not a development_dependency.
- If ruby-head fails, don't stop the other tests

.github/workflows/ruby.yml

@@ -19,7 +19,8 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['3.1', '3.2', '3.3']
+        ruby-version: ['3.1', '3.2', '3.3', '3.4', 'ruby-head']
+    continue-on-error: ${{ matrix.ruby-version == 'ruby-head' }}
 
     steps:
     - uses: actions/checkout@v4

.rubocop.yml

@@ -1,9 +1,8 @@
 inherit_from: .rubocop_todo.yml
 
-# Do not attempt to police vendored code
 AllCops:
   NewCops: enable
-  TargetRubyVersion: 3.1
+  # Do not attempt to police vendored code
   Exclude:
     - 'vendor/**/*'
 

oxidized.gemspec

@@ -35,7 +35,7 @@ Gem::Specification.new do |s|
 
   s.add_development_dependency 'bundler',             '~> 2.2'
   s.add_development_dependency 'git',                 '~> 2'
-  s.add_development_dependency 'minitest',            '~> 5.18'
+  s.add_development_dependency 'minitest',            '~> 5.25.4'
   s.add_development_dependency 'mocha',               '~> 2.1'
   s.add_development_dependency 'pry',                 '~> 0.15.0'
   s.add_development_dependency 'rake',                '~> 13.0'
@@ -49,5 +49,5 @@ Gem::Specification.new do |s|
 
   # Dependencies on optional libraries, used for unit tests & development
   s.add_development_dependency 'oxidized-web',        '>= 0.14.0'
-  s.add_development_dependency 'sequel',              '~> 5.63'
+  s.add_development_dependency 'sequel',              '~> 5.88.0'
 end