Update Amplitude ios sdk version

[sputh]

From the changelog:

4.8.1 (September 19, 2019)

• Suppress NSLogs for non-dev environments.

4.8.0 (September 3, 2019)

• Identify Macs for Mac Catalyst support.

4.7.1 (August 20, 2019)

• Fix issue where tag wasn't included in tag spec

4.7.0 (August 20, 2019)

• Fix bug where background task might be stopped before final events are flushed
• Revert logic to restore db from memory on potential db resets

4.6.0 (March 1, 2019)

• Add support for installing on tvOS platform via Carthage
• Do not use IDFV or IDFA for device ID if disabled via tracking options
• Close Sqlite DB object even if open fails
• Made startOrContinueSession public method. Only call this if you know what you are doing. This may trigger a new session to start.
• Properly end background event flush task
• Increased minimum iOS deployment target to 8.0

4.5.0 (December 18, 2018)

• Add ability to set a custom server URL for uploading events using setServerUrl.

4.4.0 (October 15, 2018)

• Add ability to set group properties via a new groupIdentifyWithGroupType method that takes in an AMPIdentify object as well as a group type and group name.

4.3.1 (August 14, 2018)

• Update SDK to better handle SQLite Exceptions.

4.3.0 (July 24, 2018)

• Add AMPTrackingOptions interface to customize the automatic tracking of user properties in the SDK (such as language, ip_address, platform, etc). See Help Center Documentation for instructions on setting up this configuration.

4.2.1 (May 21, 2018)

• Fix a bunch of compiler warnings
• Fix SSLPinning import so that it doesn't corrupt debug console. Thanks to @rob-keepsafe for the PR

4.2.0 (April 19, 2018)

• Added a setUserId method with optional boolean argument startNewSession, which when YES starts a new session after changing the userId.

4.1.0 (February 27, 2018)

• Add option to disable IDFA tracking. To disable IDFA tracking call [[Amplitude instance] disableIdfaTracking]; before initializing with your API key.

[sputh]

@CarlosMecha @f2prateek 🙏 please take a look

[CarlosMecha]

Hi @sputh ! Thanks for the PR. I've notified our engineering team, we'll prioritize and have it checked soon.

[migs647]

Since updated. Closing.