Update version and changelog for 0.15.0

Author: designatednerd

CHANGELOG.md

@@ -1,5 +1,22 @@
 # Change log
 
+### v0.15.0
+- **BREAKING**: Finally swapped out `URLSessionConfiguration` on initializer for `HTTPNetworkTransport` to use `URLSession` directly instead. If you were previously passing in a configuration, first hand it to a `URLSession` instance and then pass that instance into the initializer. 
+
+  This allows many new things including: 
+    - Support for background sessions
+    - Easier mocking through `NSURLProtocol`
+    - Certificate pinning
+    - Self-signed certificates
+    - Metrics inspection
+    - Authentication challenge handling
+ 
+ All these are pretty much entirely through the ability to use `URLSessionDelegate` directly since we're now accepting a `URLSession` you can declare yourself to be the delegate of rather than just the configuration. ([#699](https://github.com/apollographql/apollo-ios/pull/699), inspired by [#265](https://github.com/apollographql/apollo-ios/pull/265))
+- **BREAKING**, though hopefully in a good way: Significant updates to the Upload functionality to make it conform more closely to the [GraphQL Upload Spec](). Also added a goodly bit of documentation around this functionality. ([#707](https://github.com/apollographql/apollo-ios/pull/707))
+- Way better support for Swift Package Manager, especially for `ApolloSQLite` and `ApolloWebSocket`. ([#674](https://github.com/apollographql/apollo-ios/pull/674))
+- Created `ApolloClientProtocol` to match all public methods of `ApolloClient` for easier mocking. ([#715](https://github.com/apollographql/apollo-ios/pull/715), inspired by [#693](https://github.com/apollographql/apollo-ios/pull/693))
+
+
 ### v0.14.0
 
 - **BREAKING** Updated codegen to use 2.17 of the Apollo CLI. Please see the [full release notes](https://github.com/apollographql/apollo-tooling/blob/master/CHANGELOG.md#apollo2170-apollo-codegen-swift0350) for that version of the CLI, but in short: 

Configuration/Shared/Project-Version.xcconfig

@@ -1 +1 @@
-CURRENT_PROJECT_VERSION = 0.14.0
+CURRENT_PROJECT_VERSION = 0.15.0