Set minimum Ruby version to 2.6.0 and enable MFA

.github/workflows/specs.yml

@@ -13,7 +13,7 @@ jobs:
 
     strategy:
       matrix:
-        ruby: ['2.5', '2.6', '2.7']
+        ruby: ['2.6', '2.7']
 
     steps:
       - name: Checkout

activeadmin_quill_editor.gemspec

@@ -14,6 +14,12 @@ Gem::Specification.new do |spec|
   spec.email         = 'mat@blocknot.es'
   spec.homepage      = 'https://github.com/blocknotes/activeadmin_quill_editor'
 
+  spec.required_ruby_version = '>= 2.6.0'
+
+  spec.metadata['homepage_uri'] = spec.homepage
+  spec.metadata['source_code_uri'] = spec.homepage
+  spec.metadata['rubygems_mfa_required'] = 'true'
+
   spec.files         = Dir['{app,lib}/**/*', 'LICENSE.txt', 'Rakefile', 'README.md']
   spec.require_paths = ['lib']