Go-SDK - 1.0.0

## [1.0.0] - January 9th, 2020
This is the General Availability release of the Go SDK.

## New Features
- feat(onTrack): Added onTrack callback. [#198](https://github.com/optimizely/go-sdk/pull/198)
- feat: Add observability metrics for event queue. [#211](https://github.com/optimizely/go-sdk/pull/211)
- feat: Implement OptimizelyConfig API. [#216](https://github.com/optimizely/go-sdk/pull/216)
- feat: Add observability metrics for event queue. [#223](https://github.com/optimizely/go-sdk/pull/223)

## Bug Fixes
- fix: Revert signature changes to PollingProjectConfigManager. [#209](https://github.com/optimizely/go-sdk/pull/209)
- fix(notification): race detected send notification issue. [#222](https://github.com/optimizely/go-sdk/pull/222)

## Breaking Changes
- refac: Execution context. [#212](https://github.com/optimizely/go-sdk/pull/212)
- refac(config): Move config interfaces back into config package. [#213](https://github.com/optimizely/go-sdk/pull/213)

https://github.com/optimizely/go-sdk/releases/tag/v1.0.0