chore: add explicit logger dependency to api and sdk gems (#1951)

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.

Co-authored-by: Kayla Reopelle <[email protected]>

Author: miry

api/opentelemetry-api.gemspec

@@ -24,6 +24,7 @@ Gem::Specification.new do |spec|
                ['LICENSE', '.yardopts']
   spec.require_paths = ['lib']
   spec.required_ruby_version = '>= 3.1'
+  spec.add_dependency 'logger'
 
   spec.add_development_dependency 'benchmark-ipsa', '~> 0.2.0'
   spec.add_development_dependency 'bundler', '>= 1.17'

sdk/opentelemetry-sdk.gemspec

@@ -25,6 +25,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
   spec.required_ruby_version = '>= 3.1'
 
+  spec.add_dependency 'logger'
   spec.add_dependency 'opentelemetry-api', '~> 1.1'
   spec.add_dependency 'opentelemetry-common', '~> 0.20'
   spec.add_dependency 'opentelemetry-registry', '~> 0.2'