Revert minimum required Ruby version to 2.6 to support macOS system Ruby

Author: amorde

.github/workflows/Specs.yml

@@ -6,7 +6,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-12]
-        ruby: [2.7, 3.0.0]
+        ruby: [system, 2.7, 3.0.0]
 
     name: ${{ matrix.os }} / Ruby ${{ matrix.ruby }}
     runs-on: ${{ matrix.os }}

cocoapods-downloader.gemspec

@@ -15,6 +15,6 @@ Gem::Specification.new do |s|
   s.files = Dir["lib/**/*.rb"] + %w{ README.markdown LICENSE }
   s.require_paths = %w{ lib }
 
-  s.required_ruby_version = '>= 2.7.4'
+  s.required_ruby_version = '>= 2.6'
   s.specification_version = 3 if s.respond_to? :specification_version
 end