Release 2.2.3 Preparation

[thomasnield]

It's been way too long since we've had a release so I'm finally getting around to it.

Rounding up PR's and other items, here is what looks to be new for Release 2.2.3:

• RxJava updated to 2.1.16
• Kotlin updated to 1.2.51
• Silence unused and platform warnings Silence unused and platform type warnings #179
• Add missing @CheckReturnValue annoations Add missing @CheckReturnValue annotations #180
• Add zero-arg flatMapIterable and concatMapIterable Add zero-arg flatMapIterable and concatMapIterable #185
• Make cast and ofType operate on wildcard types rather than Any Make cast and ofType operate on wildcard types rather than Any #176
• Add Flowables.create with lambda as last parameter Flowable.create with lambda as last parameter #188
• Change return type of Flowable.withLatestFrom Change return type of one of the Flowable.withLatestFrom's to Flowable #193

@stepango @JakeWharton @gildor, please let me know if I missed anything and indicate any approval/disapproval if you ever have a moment. I'll release this in about two days.

[akarnokd]

FYI, the next releases of RxJava are due within two weeks:

• 2.1.17 on July 23, 2018: 2.1.17 release preparations RxJava#6089
• 2.2.0 on July 31, 2018: 2.2 release preparations RxJava#6092

[thomasnield]

@akarnokd thanks for the heads up, I'll look at changes and see if it's worth waiting for...

[thomasnield]

I may promote this to a breaking release version 2.3.0, aligned with RxJava 2.2.0.

I'm also trying to not let my OCD bother the fact RxKotlin and RxJava are not synchronized in release numbers, but they never have been anyway.

[bemusementpark]

2.2.0 is out now!

https://github.com/ReactiveX/RxJava/releases/tag/v2.2.0

[thomasnield]

@bemusementpark affirmative, I'll try to do a release today.