Fix podspec screenshot URL

Author: indragiek

InAppViewDebugger.podspec

@@ -3,7 +3,7 @@ Pod::Spec.new do |spec|
   spec.version            = "1.0.0"
   spec.summary            = "A UIView debugger (like Reveal or Xcode) that can be embedded in an app for on-device view debugging."
   spec.homepage           = "https://github.com/indragiek/InAppViewDebugger"
-  spec.screenshots        = "https://raw.githubusercontent.com/indragiek/InAppViewDebugger/master/images/main.png"
+  spec.screenshots        = "https://raw.githubusercontent.com/indragiek/InAppViewDebugger/master/docs/img/main.png"
   spec.license            = { :type => "MIT", :file => "LICENSE" }
   spec.author             = { "Indragie Karunaratne" => "[email protected]" }
   spec.social_media_url   = "https://twitter.com/indragie"