Add support for jruby 10.1

[larouxn]

Is your feature request related to a problem? Please describe.

It would be nice to see latest jruby 10.1 supported.

Inspired by #3000

Describe the solution you'd like

jruby 10.1 should be added to the CI config and the codebase updated to support it. That said it may already work just fine without any runtime code changes.

Describe alternatives you've considered

Not an alternative but I already tried adding it and it failed CI due to pry-nav, see: #3000 (comment).

Additional context

See the PR and comment linked above.

[larouxn]

What do we think about doing this as a way to unblock CI from running against jruby 10.1?

diff --git a/elasticsearch-api/Gemfile b/elasticsearch-api/Gemfile
index fd00bfdf..4a9ee6fc 100644
--- a/elasticsearch-api/Gemfile
+++ b/elasticsearch-api/Gemfile
@@ -28,7 +28,7 @@ group :development do
   gem 'rspec'
   gem 'rspec_junit_formatter'
   if defined?(JRUBY_VERSION)
-    gem 'pry-nav'
+    gem 'pry-nav' if Gem::Version.new(JRUBY_VERSION) < Gem::Version.new('10.1')
   else
     gem 'debug'
   end
diff --git a/elasticsearch-api/spec/spec_helper.rb b/elasticsearch-api/spec/spec_helper.rb
index aa79707a..aa0df0dd 100644
--- a/elasticsearch-api/spec/spec_helper.rb
+++ b/elasticsearch-api/spec/spec_helper.rb
@@ -22,7 +22,12 @@ if ENV['COVERAGE']
 end
 
 if defined?(JRUBY_VERSION)
-  require 'pry-nav'
+  if Gem::Version.new(JRUBY_VERSION) < Gem::Version.new('10.1')
+    begin
+      require 'pry-nav'
+    rescue LoadError
+    end
+  end
 else
   require 'debug'
 end