Bump compileSdkVersion to 28 and buildToolsVersion to 28.0.2

[dulmandakh]

This PR will bump compileSdkVersion to 28 and buildToolsVersion to 28.0.2, which was released a few days ago.

I decided to split #20026 into smaller, easy to review PRs.

Test Plan:

Everything builds and runs as normal

Release Notes:

[ANDROID] [ENHANCEMENT] [SDK] - Bump Android SDK to 28

[facebook-github-bot]

hramos has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[dulmandakh]

@hramos any updates?

[dulmandakh]

IMHO, there will be no change on how RN behaves because we retained targetSdkVersion.

[hramos]

Gradle changes look OK to me, but I'm not sure if we can land the change to .buckconfig just yet as we're using android-26 elsewhere in the mono repo. The internal diff is waiting for review from someone with more insight into how React Native is consumed by our internal Android consumers. It looks like it should be good to go (all tests pass), but I don't feel comfortable landing this on a Friday afternoon.

[hramos]

This one is still waiting for approval from a teammate.

[dulmandakh]

@hramos maybe merge #20777, which is used by many FB projects.

[dulmandakh]

closing this PR, will create another PR once SDK 28 and support library 28.x released.

[hramos]

I recently had to undo the bump to SDK 27 (and then add it back), so I'll add some more context in this PR for future reference. Hopefully this will be useful to myself, or whoever works on adding support for SDK 28.

Outright, I don't think we need to land support for 28 just yet. Google will not start requiring SDK 28 for new apps until August 2020.

In order to import this, whenever we decide it's needed, we'll first need to make sure the SDK is officially supported by Facebook's internal build system. As of this writing, we only support SDKs up to API 26.

Facebook employees can look at D9929066 to see how it's possible to use SDK 27 and 28 for running tests, prior to official support becoming available.

[gengjiawen]

looks like the undo commit break ci build, can you check that ?

[dulmandakh]

@gengjiawen working on it 👍