Creating CHANGELOG for FCM (firebase#764)

* add CHANGELOG for FCM

* fix the typo

Author: charlotteliang

Firebase/Messaging/CHANGELOG.md

@@ -0,0 +1,85 @@
+# 2018-02-06 -- v2.1.0
+- Added a new property autoInitEnabled to enable and disable FCM token auto generation.
+- Fixed an issue where notification delivery would fail after changing language settings.
+
+# 2017-09-26 -- v2.0.5
+- Added swizzling of additional UNUserNotificationCenterDelegate method, for
+  more accurate Analytics logging.
+- Fixed a swizzling issue with unimplemented UNUserNotificationCenterDelegate
+  methods.
+
+# 2017-09-26 -- v2.0.4
+- Fixed an issue where the FCM token was not associating correctly with an APNs
+  device token, depending on when the APNs device token was made available.
+- Fixed an issue where FCM tokens for different Sender IDs were not associating
+  correctly with an APNs device token.
+- Fixed an issue that was preventing the FCM direct channel from being
+  established on the first start after 24 hours of being opened.
+- Clarified a log message about method swizzling being enabled.
+
+# 2017-09-13 -- v2.0.3
+- Moved to safer use of NSAsserts, instead of lower-level `__builtin_trap()`
+  method.
+- Added logging of the underlying error code for an error trying to create or
+  open an internal database file.
+
+# 2017-08-25 -- v2.0.2
+- Removed old logic which was saving the SDK version to NSUserDefaults.
+
+# 2017-08-07 -- v2.0.1
+- Fixed an issue where setting `shouldEstablishDirectChannel` in a background
+  thread was triggering the Main Thread Sanitizer in Xcode 9.
+- Removed some old logic related to logging.
+- Added some additional logging around errors while method swizzling.
+
+# 2017-05-03 -- v2.0.0
+- Introduced an improved interface for Swift 3 developers
+- Added new properties and methods to simplify FCM token management
+- Added property, APNSToken, to simplify APNs token management
+- Added new delegate method to be notified of FCM token refreshes
+- Added new property, shouldEstablishDirectChannel, to simplify connecting
+  directly to FCM
+
+# 2017-03-31 -- v1.2.3
+
+- Fixed an issue where custom UNNotificationCenterDelegates may not have been
+  swizzled (if swizzling was enabled)
+- Fixed a issue iOS 8.0 and 8.1 devices using scheduled notifications
+- Improvements to console logging
+
+# 2017-01-31 -- v1.2.2
+
+- Improved topic subscription logic for more reliable subscriptions.
+- Reduced memory footprint and CPU usage when subscribing to multiple topics.
+- Better documentation in the public headers.
+- Switched from ProtocolBuffers2 to protobuf compiler.
+
+# 2016-10-12 -- v1.2.1
+
+- Better documentation on the public headers.
+
+# 2016-09-02 -- v1.2.0
+
+- Support the UserNotifications framework introduced in iOS 10.
+- Add a new API, -applicationReceivedRemoteMessage:, to FIRMessaging. This
+  allows apps to receive data messages from FCM on devices running iOS 10 and
+  above.
+
+# 2016-07-06 -- v1.1.1
+
+- Move FIRMessaging related plists to ApplicationSupport directory.
+
+# 2016-05-04 -- v1.1.0
+
+- Change flag to disable swizzling to *FirebaseAppDelegateProxyEnabled*.
+- '[FIRMessaging appDidReceiveMessage:] returns FIRMessagingMessageInfo object.
+- Minor bug fixes.
+
+# 2016-01-25 -- v1.0.2
+
+- Accept topic names without /topics prefix.
+- Add Swift annotations to public static accessors.
+
+# 2016-01-25 -- v1.0.0
+
+- New Firebase messaging API.