Remove ruby 2.5 support, it's EOL since over half a year

.github/workflows/ci.yml

@@ -17,7 +17,6 @@ jobs:
           - 3.0
           - 2.7
           - 2.6
-          - 2.5
         gemfile:
           - Gemfile
           - test/gemfiles/no-rails.Gemfile

.rubocop.yml

@@ -1,7 +1,7 @@
 require: rubocop-rails
 
 AllCops:
-  TargetRubyVersion: 2.5
+  TargetRubyVersion: 2.6
   NewCops: enable
   Exclude:
     - "bin/**/*"

diaspora_federation-json_schema.gemspec

@@ -19,5 +19,5 @@ Gem::Specification.new do |s|
 
   s.files       = Dir["lib/diaspora_federation/schemas.rb", "lib/diaspora_federation/schemas/*.json"]
 
-  s.required_ruby_version = ">= 2.5"
+  s.required_ruby_version = ">= 2.6"
 end

diaspora_federation-rails.gemspec

@@ -19,7 +19,7 @@ Gem::Specification.new do |s|
   s.files       = Dir["app/**/*", "config/routes.rb", "config/initializers/*",
                       "lib/diaspora_federation/{engine,rails}.rb", "LICENSE", "README.md", "Changelog.md"]
 
-  s.required_ruby_version = ">= 2.5"
+  s.required_ruby_version = ">= 2.6"
 
   s.add_dependency "actionpack", ">= 5.2", "< 7"
 

diaspora_federation-test.gemspec

@@ -19,7 +19,7 @@ Gem::Specification.new do |s|
 
   s.files       = Dir["lib/diaspora_federation/test.rb", "lib/diaspora_federation/test/*"]
 
-  s.required_ruby_version = ">= 2.5"
+  s.required_ruby_version = ">= 2.6"
 
   s.add_dependency "diaspora_federation", DiasporaFederation::VERSION
   s.add_dependency "fabrication", "~> 2.16"

diaspora_federation.gemspec

@@ -24,7 +24,7 @@ Gem::Specification.new do |s|
                         "lib/diaspora_federation/test/*",
                         "lib/tasks/*.rake"]
 
-  s.required_ruby_version = ">= 2.5"
+  s.required_ruby_version = ">= 2.6"
 
   s.add_dependency "faraday", "~> 1.0"
   s.add_dependency "faraday_middleware", "~> 1.0"