Declare framework dependencies in podspec (slackhq#666)

Users may want to build the pod with Clang modules disabled `-fno-modules` because they are using `ccache` which doesn't support `-fmodules`. When modules are disabled, auto-linking of framework modules is also disabled, so these dependencies need to be expressed explicitly.

Author: jgavris

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Change Log
 
+## [Version 1.9.7](https://github.com/slackhq/SlackTextViewController/releases/tag/v1.9.7)
+
+#### Features:
+
+- Enables building the CocoaPod with `CLANG_MODULES_ENABLED=NO` which enables compiling with `ccache`.
+
 ## [Version 1.9.6](https://github.com/slackhq/SlackTextViewController/releases/tag/v1.9.6)
 
 This release includes many iOS 11 and iPhone X hot fixes.

SlackTextViewController.podspec

@@ -11,6 +11,7 @@ Pod::Spec.new do |s|
   s.author       		= { "Slack Technologies, Inc." => "ios-team@slack-corp.com" }
   s.source          = { :git => "https://github.com/slackhq/SlackTextViewController.git", :tag => "v#{s.version}" }
 
+  s.frameworks    	= 'CoreGraphics', 'UIKit'
   s.platform     		= :ios, "7.0"
   s.requires_arc 		= true