4.0.0 breaks compatibility with ES Versions < 8.0.0

[Jan Hübner]

Also see kokuwaio/helm-charts#108

[Jan Hübner]

Fixed it for my use case with:

diff --git a/Gemfile b/Gemfile
index 8868bf6..78f072d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,7 +1,8 @@
 source 'https://rubygems.org'

 gem 'activesupport', '7.0.2.3'
-gem 'elasticsearch-xpack', '7.17.1'
+gem 'elasticsearch-xpack', '7.10.1'
 gem 'fluentd', '1.14.6'
 gem 'fluent-plugin-concat', '2.5.0'
 gem 'fluent-plugin-detect-exceptions', '0.0.14'

I suppose support of older versions is not intended by the project.