Add version constraint to logger dependency

Use pessimistic version constraint (~> 1.6) to ensure build
reproducibility and prevent accidentally pulling in future versions
with potential breaking changes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: pimpin

couchbase-orm.gemspec

@@ -23,7 +23,7 @@ Gem::Specification.new do |gem|
   gem.add_runtime_dependency     'couchbase',    '>= 3.4.2'
   gem.add_runtime_dependency     'radix',        '~> 2.2' # converting numbers to and from any base
   gem.add_runtime_dependency     'json-schema',  '>= 3' # validating JSON against a schema
-  gem.add_runtime_dependency     'logger' # Required from Ruby 3.5.0+
+  gem.add_runtime_dependency     'logger',       '~> 1.6' # Required from Ruby 3.5.0+
 
   gem.add_development_dependency 'rake', '~> 12.2'
   gem.add_development_dependency 'rspec', '~> 3.7'