Update gemspec file to recent styles (#212)

- `date` and `rubygems_version` should not be set
- Remove deprecated `test_files` to shrink gem size
- Update homepage to https

yajl-ruby.gemspec

@@ -5,15 +5,12 @@ Gem::Specification.new do |s|
   s.version = Yajl::VERSION
   s.license = "MIT"
   s.authors = ["Brian Lopez", "Lloyd Hilaiel"]
-  s.date = Time.now.utc.strftime("%Y-%m-%d")
   s.email = %q{[email protected]}
   s.extensions = ["ext/yajl/extconf.rb"]
   s.files = `git ls-files`.split("\n")
-  s.homepage = %q{http://github.com/brianmario/yajl-ruby}
+  s.homepage = %q{https://github.com/brianmario/yajl-ruby}
   s.require_paths = ["lib"]
-  s.rubygems_version = %q{1.4.2}
   s.summary = %q{Ruby C bindings to the excellent Yajl JSON stream-based parser library.}
-  s.test_files = `git ls-files spec examples`.split("\n")
   s.required_ruby_version = ">= 2.6.0"
 
   # tests