Remove more depedencies which are unnecessary

Gemfile.lock

@@ -2,12 +2,9 @@ PATH
   remote: .
   specs:
     entitlements-github-plugin (0.0.2)
-      concurrent-ruby (= 1.1.9)
-      contracts (= 0.16.0)
+      entitlements (= 0.1.8)
       faraday (>= 1, < 3)
-      net-ldap (~> 0.17.0)
       octokit (~> 4.25)
-      optimist (= 3.0.0)
 
 GEM
   remote: https://rubygems.org/
@@ -118,7 +115,6 @@ PLATFORMS
 
 DEPENDENCIES
   contracts-rspec (= 0.1.0)
-  entitlements (= 0.1.8)
   entitlements-github-plugin!
   rake (= 13.0.6)
   rspec (= 3.8.0)

entitlements-github-plugin.gemspec

@@ -12,15 +12,11 @@ Gem::Specification.new do |s|
   s.homepage = "https://github.com/github/entitlements-github-plugin"
   s.executables = %w[]
 
-  s.add_dependency "concurrent-ruby", "= 1.1.9"
-  s.add_dependency "contracts", "= 0.16.0"
+  s.add_dependency "entitlements", "0.1.8"
   s.add_dependency "faraday", "< 3", ">= 1"
-  s.add_dependency "net-ldap", "~> 0.17.0"
   s.add_dependency "octokit", "~> 4.25"
-  s.add_dependency "optimist", "= 3.0.0"
 
   s.add_development_dependency "contracts-rspec", "= 0.1.0"
-  s.add_development_dependency "entitlements", "0.1.8"
   s.add_development_dependency "rake", "= 13.0.6"
   s.add_development_dependency "rspec", "= 3.8.0"
   s.add_development_dependency "rspec-core", "= 3.8.0"