Added static lib support for cocoapods (#968)

* Added static lib support for cocoapods

* Update README.md

Co-authored-by: LRubin <[email protected]>

Author: migs647

Analytics.podspec

@@ -17,7 +17,9 @@ Pod::Spec.new do |s|
 
   s.ios.deployment_target = '10.0'
   s.tvos.deployment_target = '10.0'
-  s.osx.deployment_target = '10.13'  
+  s.osx.deployment_target = '10.13'
+
+  s.static_framework = true  
 
   s.source_files = [
     'Segment/Classes/**/*.{h,m}',

README.md

@@ -61,6 +61,7 @@ Analytics is available through [CocoaPods](http://cocoapods.org) and [Carthage](
 ```ruby
 pod "Analytics", "3.7.0"
 ```
+Note: Segment _strongly_ recommends that you use a dynamic framework to manage your project dependencies. If you prefer static libraries, you can add `use_modular_headers!` or `use_frameworks! :linkage => :static` in your Podfile. However, you must then _manually update_ all of your dependencies on a regular schedule.
 
 ### Carthage