Update ruby Docker tag to v3

Author: renovate[bot]

.gitlab-ci.yml

@@ -94,21 +94,21 @@ variables:
 #-----------------------------------------------------------------------
 
 .pup_6_x: &pup_6_x
-  image: 'ruby:2.5'
+  image: 'ruby:3.4'
   variables:
     PUPPET_VERSION: '~> 6.0'
     BEAKER_PUPPET_COLLECTION: 'puppet6'
     MATRIX_RUBY_VERSION: '2.5'
 
 .pup_6_pe: &pup_6_pe
-  image: 'ruby:2.5'
+  image: 'ruby:3.4'
   variables:
     PUPPET_VERSION: '6.22.1'
     BEAKER_PUPPET_COLLECTION: 'puppet6'
     MATRIX_RUBY_VERSION: '2.5'
 
 .pup_7_x: &pup_7_x
-  image: 'ruby:2.7'
+  image: 'ruby:3.4'
   variables:
     PUPPET_VERSION: '~> 7.0'
     BEAKER_PUPPET_COLLECTION: 'puppet7'