Drop Puppet 7 support

Puppet 7 is EoL since November 2024, and our dependencies dropped
support for it "already".

Author: bastelfreak

Gemfile

@@ -3,7 +3,7 @@
 
 source 'https://rubygems.org'
 
-gem 'puppet', ENV.fetch('PUPPET_GEM_VERSION', '>= 7'), groups: ['development', 'test']
+gem 'puppet', ENV.fetch('PUPPET_GEM_VERSION', '>= 8'), groups: ['development', 'test']
 gem 'rake'
 
 gem 'kafo_module_lint', {"groups"=>["test"]}

metadata.json

@@ -48,7 +48,7 @@
   "requirements": [
     {
       "name": "puppet",
-      "version_requirement": ">= 7.0.0 < 9.0.0"
+      "version_requirement": ">= 8.0.0 < 9.0.0"
     }
   ],
   "operatingsystem_support": [