Added the missing licenses field to some default gems

lib/English.gemspec

@@ -8,6 +8,7 @@ Gem::Specification.new do |spec|
   spec.description   = %q{Require 'English.rb' to reference global variables with less cryptic names.}
   spec.homepage      = "https://github.com/ruby/English"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
+  spec.licenses       = ["Ruby", "BSD-2-Clause"]
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage

lib/net/http/net-http.gemspec

@@ -17,6 +17,7 @@ Gem::Specification.new do |spec|
   spec.description   = %q{HTTP client api for Ruby.}
   spec.homepage      = "https://github.com/ruby/net-http"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.6.0")
+  spec.licenses      = ["Ruby", "BSD-2-Clause"]
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage

lib/net/net-ftp.gemspec

@@ -17,6 +17,7 @@ Gem::Specification.new do |spec|
   spec.description   = %q{Support for the File Transfer Protocol.}
   spec.homepage      = "https://github.com/ruby/net-ftp"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
+  spec.licenses      = ["Ruby", "BSD-2-Clause"]
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage

lib/net/net-imap.gemspec

@@ -17,6 +17,7 @@ Gem::Specification.new do |spec|
   spec.description   = %q{Ruby client api for Internet Message Access Protocol}
   spec.homepage      = "https://github.com/ruby/net-imap"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.5.0")
+  spec.licenses       = ["Ruby", "BSD-2-Clause"]
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage

lib/net/net-protocol.gemspec

@@ -17,6 +17,7 @@ Gem::Specification.new do |spec|
   spec.description   = %q{The abstruct interface for net-* client.}
   spec.homepage      = "https://github.com/ruby/net-protocol"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
+  spec.licenses      = ["Ruby", "BSD-2-Clause"]
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage

lib/optparse/optparse.gemspec

@@ -17,6 +17,7 @@ Gem::Specification.new do |spec|
   spec.description   = %q{OptionParser is a class for command-line option analysis.}
   spec.homepage      = "https://github.com/ruby/optparse"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.5.0")
+  spec.licenses      = ["Ruby", "BSD-2-Clause"]
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage

lib/tempfile.gemspec

@@ -8,6 +8,7 @@ Gem::Specification.new do |spec|
   spec.description   = %q{A utility class for managing temporary files.}
   spec.homepage      = "https://github.com/ruby/tempfile"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.5.0")
+  spec.licenses      = ["Ruby", "BSD-2-Clause"]
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage

lib/tmpdir.gemspec

@@ -8,6 +8,7 @@ Gem::Specification.new do |spec|
   spec.description   = %q{Extends the Dir class to manage the OS temporary file path.}
   spec.homepage      = "https://github.com/ruby/tmpdir"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
+  spec.licenses      = ["Ruby", "BSD-2-Clause"]
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage