chore(deps): update dependency opentelemetry-sdk-experimental to '~> 0.6.0' (#2351)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

instrumentation/rack/Gemfile

@@ -12,7 +12,7 @@ group :test do
   gem 'appraisal', '~> 2.5.0'
   gem 'minitest', '~> 6.0.0'
   gem 'opentelemetry-sdk', '~> 1.11.0'
-  gem 'opentelemetry-sdk-experimental', '~> 0.5.0'
+  gem 'opentelemetry-sdk-experimental', '~> 0.6.0'
   gem 'opentelemetry-test-helpers', '~> 0.8.0'
   gem 'rake', '>= 13'
   gem 'rubocop', '~> 1.86.0'