Ensure URI.from_path is available to minitest runner

[andyw8]

When starting to verify this with Rails, I discovered the we need to ensure URI.from_path is available (it's already there for test-unit), since we use it in uri_from_test_class.

[Morriar]

What's up with the Rubocop tests?

[andyw8]

RuboCop is fine, but something is failing for Ruby 3.1. Looking into.

[andyw8]

I modified the test to show the underlying failure:

Failure:
RubyLsp::MinitestTestRunnerTest#test_minitest_output [/home/runner/work/ruby-lsp/ruby-lsp/test/minitest_test_runner_test.rb:19]
Minitest::Assertion: command failed: <internal:/opt/hostedtoolcache/Ruby/3.1.6/x64/lib/ruby/3.1.0/rubygems/core_ext/kernel_require.rb>:85:in `require': cannot load such file -- ruby_indexer/lib/ruby_indexer/uri (LoadError)
	from <internal:/opt/hostedtoolcache/Ruby/3.1.6/x64/lib/ruby/3.1.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
	from /home/runner/work/ruby-lsp/ruby-lsp/lib/ruby_lsp/ruby_lsp_reporter_plugin.rb:5:in `<top (required)>'
	from <internal:/opt/hostedtoolcache/Ruby/3.1.6/x64/lib/ruby/3.1.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
	from <internal:/opt/hostedtoolcache/Ruby/3.1.6/x64/lib/ruby/3.1.0/rubygems/core_ext/kernel_require.rb>:85:in `require'

It seems there is some issue with the load path. Since it only affects a Ruby version which is EOL in 2 weeks, and is only in our test code, I'm not to spend much time on this. The latest commit works around it by requiring bundler explicitly.