maint: Drop runtime dependency on base64

Gemfile

@@ -19,6 +19,7 @@ group :test do
   install_if -> { RUBY_VERSION >= '2.8' } do
     gem 'rexml', '>= 3.2.4'
   end
+  gem 'base64'
   gem 'json', '>= 2.3.0'
   gem 'jwt', '~> 2.2', '>= 2.2.1'
   gem 'mime-types', '~> 3.3', '>= 3.3.1'

lib/octokit/client/code_scanning.rb

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require 'base64'
 require 'tempfile'
 require 'zlib'
 
@@ -45,7 +44,7 @@ def compress_sarif_data(file)
           Zlib::GzipWriter.open(tempfile) do |gz_file|
             gz_file.write File.binread(file)
           end
-          Base64.strict_encode64(tempfile.read)
+          [tempfile.read].pack('m0') # Base64.strict_encode64
         end
       end
     end

lib/octokit/client/contents.rb

@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require 'base64'
-
 module Octokit
   class Client
     # Methods for the Repo Contents API
@@ -80,7 +78,7 @@ def create_contents(*args)
         end
         raise ArgumentError, 'content or :file option required' if content.nil?
 
-        options[:content] = Base64.strict_encode64(content)
+        options[:content] = [content].pack('m0') # Base64.strict_encode64
         options[:message] = message
         url = "#{Repository.path repo}/contents/#{path}"
         put url, options

octokit.gemspec

@@ -5,7 +5,6 @@ $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require 'octokit/version'
 
 Gem::Specification.new do |spec|
-  spec.add_dependency 'base64'
   spec.add_dependency 'faraday', '>= 1', '< 3'
   spec.add_dependency 'sawyer', '~> 0.9'
   spec.authors = ['Wynn Netherland', 'Erik Michaels-Ober', 'Clint Shryock']

spec/octokit/client/licenses_spec.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'base64'
+
 describe Octokit::Client::Licenses do
   describe '.licenses', :vcr do
     it 'returns all licenses' do