prepare 6.2.4 release (#185)

Author: LaunchDarklyReleaseBot

launchdarkly-server-sdk.gemspec

@@ -36,10 +36,8 @@ Gem::Specification.new do |spec|
 
   spec.add_runtime_dependency "semantic", "~> 1.6"
   spec.add_runtime_dependency "concurrent-ruby", "~> 1.1"
-  spec.add_runtime_dependency "ld-eventsource", "~> 2.0"
+  spec.add_runtime_dependency "ld-eventsource", "2.0.1"
 
-  # lock json to 2.3.x as ruby libraries often remove
-  # support for older ruby versions in minor releases
-  spec.add_runtime_dependency "json", "~> 2.3.1"
-  spec.add_runtime_dependency "http", "~> 4.4.1"
+  spec.add_runtime_dependency "json", "~> 2.3"
+  spec.add_runtime_dependency "http", ">= 4.4.0", "< 6.0.0"
 end