Include public certificate

This gem is cryptographically signed. To be sure the gem you install hasn’t been tampered with:
Add certs/opensearch-rubygems.pem (if you haven’t already) as a trusted certificate
gem cert --add <(curl -Ls certs/opensearch-rubygems.pem)
gem install logstash-output-openserach -P HighSecurity
The HighSecurity trust profile will verify signed gems, and allow only if all the dependencies are signed.
This is created by following https://guides.rubygems.org/security/#building-gems

Signed-off-by: Vijayan Balasubramanian <balasvij@amazon.com>

Author: VijayanB

certs/opensearch-rubygems.pem

@@ -0,0 +1,21 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

logstash-output-opensearch.gemspec

@@ -18,6 +18,8 @@ Gem::Specification.new do |s|
   # Tests
   s.test_files = s.files.grep(%r{^(test|spec|features)/})
 
+  s.cert_chain  = ['certs/opensearch-rubygems.pem']
+
   # Special flag to let us know this is actually a logstash plugin
   s.metadata = {
     "logstash_plugin" => "true",