Revert CocoaPods version.

Alamofire.podspec

@@ -9,8 +9,6 @@ Pod::Spec.new do |s|
   s.source = { :git => 'https://github.com/Alamofire/Alamofire.git', :tag => s.version }
   s.documentation_url = 'https://alamofire.github.io/Alamofire/'
 
-  # s.swift_versions = ['3', '4', '4.2']
-
   s.ios.deployment_target = '8.0'
   s.osx.deployment_target = '10.10'
   s.tvos.deployment_target = '9.0'

Gemfile

@@ -1,5 +1,5 @@
 source "https://rubygems.org"
 
-gem "cocoapods", git: "https://github.com/CocoaPods/CocoaPods"
+gem "cocoapods", "~> 1.6.0.beta.2"
 gem "xcpretty"
 gem "jazzy"

Gemfile.lock

@@ -1,7 +1,14 @@
-GIT
-  remote: https://github.com/CocoaPods/CocoaPods
-  revision: aa28bd59c4a6400a2385a4142be036c994ae870a
+GEM
+  remote: https://rubygems.org/
   specs:
+    CFPropertyList (3.0.0)
+    activesupport (4.2.10)
+      i18n (~> 0.7)
+      minitest (~> 5.1)
+      thread_safe (~> 0.3, >= 0.3.4)
+      tzinfo (~> 1.1)
+    atomos (0.1.3)
+    claide (1.0.2)
     cocoapods (1.6.0.beta.2)
       activesupport (>= 4.0.2, < 5)
       claide (>= 1.0.2, < 2.0)
@@ -15,24 +22,12 @@ GIT
       cocoapods-try (>= 1.1.0, < 2.0)
       colored2 (~> 3.1)
       escape (~> 0.0.4)
-      fourflusher (~> 2.1.0)
+      fourflusher (~> 2.0.1)
       gh_inspector (~> 1.0)
       molinillo (~> 0.6.6)
       nap (~> 1.0)
       ruby-macho (~> 1.3, >= 1.3.1)
       xcodeproj (>= 1.7.0, < 2.0)
-
-GEM
-  remote: https://rubygems.org/
-  specs:
-    CFPropertyList (3.0.0)
-    activesupport (4.2.10)
-      i18n (~> 0.7)
-      minitest (~> 5.1)
-      thread_safe (~> 0.3, >= 0.3.4)
-      tzinfo (~> 1.1)
-    atomos (0.1.3)
-    claide (1.0.2)
     cocoapods-core (1.6.0.beta.2)
       activesupport (>= 4.0.2, < 6)
       fuzzy_match (~> 2.0.4)
@@ -51,7 +46,7 @@ GEM
     concurrent-ruby (1.1.3)
     escape (0.0.4)
     ffi (1.9.25)
-    fourflusher (2.1.0)
+    fourflusher (2.0.1)
     fuzzy_match (2.0.4)
     gh_inspector (1.1.3)
     i18n (0.9.5)
@@ -103,7 +98,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  cocoapods!
+  cocoapods (~> 1.6.0.beta.2)
   jazzy
   xcpretty