Redmine 5 support

[delanym]

Probably just need to update gems and try again

redmine-1     | LoadError: cannot load such file -- redmine_user_specific_theme (LoadError)
redmine-1     | <internal:/usr/local/lib/ruby/3.2.0/rubygems/core_ext/kernel_require.rb>:38:in `require'
redmine-1     | <internal:/usr/local/lib/ruby/3.2.0/rubygems/core_ext/kernel_require.rb>:38:in `require'
redmine-1     | /usr/local/bundle/gems/zeitwerk-2.6.16/lib/zeitwerk/kernel.rb:34:in `require'
redmine-1     | /usr/src/redmine/plugins/redmine_user_specific_theme/init.rb:13:in `<top (required)>'