feat: add explicit logger dependency to api and sdk gems

[miry]

The logger library will be removed from Ruby’s default gems starting with version 3.5.0, so it needs to be declared explicitly as a dependency.

$ grep "require 'logger'" -R .
./api/lib/opentelemetry.rb:require 'logger'
./api/test/opentelemetry/context_test.rb:require 'logger'
./sdk/lib/opentelemetry/sdk/forwarding_logger.rb:require 'logger'
./test_helpers/lib/opentelemetry/test_helpers.rb:require 'logger'

[kaylareopelle]

Thanks for submitting this, @miry! I'm going to change the conventional commit message in your PR title to to feat so this change kicks off a release.