update gemspec

Author: khiga8

erblint-github.gemspec

@@ -4,7 +4,7 @@ Gem::Specification.new do |s|
   s.name = "erblint-github"
   s.version = "0.0.1"
   s.summary = "erblint GitHub"
-  s.description = "Code style checking for GitHub Ruby repositories"
+  s.description = "Template style checking for GitHub Ruby repositories"
   s.homepage = "https://github.com/github/erblint-github"
   s.license = "MIT"
 
@@ -16,12 +16,9 @@ Gem::Specification.new do |s|
   s.email = ["[email protected]"]
   s.authors = ["GitHub Open Source"]
 
-  s.add_runtime_dependency     "actionview", ">= 5.0.0"
-  s.add_runtime_dependency     "activesupport", ">= 5.0.0"
-
-  s.add_development_dependency "erb_lint"
+  s.add_development_dependency "erb_lint", "~> 0.1"
   s.add_development_dependency "minitest", "~> 5.14"
-  s.add_development_dependency "mocha"
+  s.add_development_dependency "mocha", "~> 1"
   s.add_development_dependency "rake", "~> 12.0"
 
   s.add_development_dependency "rubocop", "= 1.13.0"