Fix older option for gem command

.gitlab-ci.yml

@@ -3,7 +3,7 @@
   before_script:
     - apk add --update ragel build-base
     - if [ "$INSTALL_OPENJDK" == "true" ]; then apk add openjdk8; fi
-    - gem install bundler --no-ri --no-rdoc
+    - gem install bundler --no-document
     - ruby --version
     - gem --version
     - bundle --version
@@ -14,10 +14,6 @@
     paths:
       - vendor/ruby
 
-Ruby 2.2:
-  image: "ruby:2.2-alpine"
-  <<: *defaults
-
 Ruby 2.3:
   image: "ruby:2.3-alpine"
   <<: *defaults
@@ -26,6 +22,14 @@ Ruby 2.4:
   image: "ruby:2.4-alpine"
   <<: *defaults
 
+Ruby 2.5:
+  image: "ruby:2.5-alpine"
+  <<: *defaults
+
+Ruby 2.6:
+  image: "ruby:2.6-alpine"
+  <<: *defaults
+
 JRuby 9.1:
   image: "jruby:9.1-alpine"
   variables: