fix oboe c-lib version to 2.0.9 for this release

Author: prettycoder

Rakefile

@@ -73,7 +73,7 @@ task :fetch_ext_deps do
   end
 
   # The c-lib version is different from the gem version
-  oboe_version = ENV['OBOE_VERSION'] || 'latest'
+  oboe_version = ENV['OBOE_VERSION'] || '2.0.9'
   oboe_src_dir = "https://s3-us-west-2.amazonaws.com/rc-files-t2/c-lib/#{oboe_version}"
   ext_src_dir = File.expand_path('ext/oboe_metal/src')