[rubygems/rubygems] Add support for mise.toml file

https://github.com/rubygems/rubygems/commit/809a2a17a7

lib/bundler/ruby_dsl.rb

@@ -42,9 +42,9 @@ module Bundler
     # Loads the file relative to the dirname of the Gemfile itself.
     def normalize_ruby_file(filename)
       file_content = Bundler.read_file(gemfile.dirname.join(filename))
-      # match "ruby-3.2.2" or "ruby   3.2.2" capturing version string up to the first space or comment
+      # match "ruby-3.2.2", ruby = "3.2.2" or "ruby   3.2.2" capturing version string up to the first space or comment
-      if /^ruby(-|\s+)([^\s#]+)/.match(file_content)
+      if /^ruby[\s-]*(?:=\s*)?"?([^\s#"]+)"?/.match(file_content)
-        $2
+        $1
       else
         file_content.strip
       end

spec/bundler/bundler/ruby_dsl_spec.rb

@@ -172,6 +172,19 @@ RSpec.describe Bundler::RubyDsl do
         end
       end
 
+      context "with a mise.toml file format" do
+        let(:file) { "mise.toml" }
+        let(:ruby_version_arg) { nil }
+        let(:file_content) do
+          <<~TOML
+            [tools]
+            ruby = "#{version}"
+          TOML
+        end
+
+        it_behaves_like "it stores the ruby version"
+      end
+
       context "with a .tool-versions file format" do
         let(:file) { ".tool-versions" }
         let(:ruby_version_arg) { nil }