Fix gemspec warnings

ttfunk.gemspec

@@ -4,14 +4,9 @@ Gem::Specification.new do |spec|
   spec.platform = Gem::Platform::RUBY
   spec.summary = "TrueType Font Metrics Parser"
   spec.description = "Font Metrics Parser for the Prawn PDF generator"
+  spec.licenses = %w[Nonstandard GPL-2.0 GPL-3.0]
 
-  spec.files = Dir.glob("lib/**/*") +
-    ['CHANGELOG.md', 'README.md', 'COPYING', 'LICENSE', 'GPLv2', 'GPLv3']
-  spec.required_ruby_version = '~> 2.1'
-  spec.add_development_dependency('rake')
-  spec.add_development_dependency('rspec')
-  spec.add_development_dependency('rubocop', '~> 0.46')
-  spec.add_development_dependency('yard')
+  spec.homepage = "https://prawnpdf.org"
 
   spec.cert_chain = ['certs/pointlessone.pem']
   if $PROGRAM_NAME.end_with? 'gem'
@@ -32,4 +27,12 @@ Gem::Specification.new do |spec|
     "greenberg@entryway.net",
     "jimmy@deefa.com"
   ]
+
+  spec.files = Dir.glob("lib/**/*") +
+    ['CHANGELOG.md', 'README.md', 'COPYING', 'LICENSE', 'GPLv2', 'GPLv3']
+  spec.required_ruby_version = '~> 2.1'
+  spec.add_development_dependency('rake', '~> 12')
+  spec.add_development_dependency('rspec', '~> 3.5')
+  spec.add_development_dependency('rubocop', '~> 0.46')
+  spec.add_development_dependency('yard', '~> 0.9')
 end