Migrate support lib dependencies to AndroidX.

[ychescale9]

Closes #331

PR migrates support lib to AndroidX:

com.android.support:support-annotations:28.0.0 -> androidx.annotation:annotation:1.0.2
com.android.support:appcompat-v7:28.0.0 -> androidx.appcompat:appcompat:1.0.2

Note that the library itself only depends on the annotation library, appcompat is used by sample app.

The following have also been updated:

• Kotlin 1.3.31
• RxJava 2.2.8
• RxAndroid 2.1.1

[codecov-io]

Codecov Report

Merging #332 into RxJava2.x will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           RxJava2.x     #332   +/-   ##
==========================================
  Coverage      83.17%   83.17%           
==========================================
  Files             11       11           
  Lines            434      434           
  Branches          33       33           
==========================================
  Hits             361      361           
  Misses            47       47           
  Partials          26       26

Impacted Files	Coverage Δ
...n/reactivenetwork/library/rx2/ReactiveNetwork.java	83.33% <ø> (ø)	⬆️
.../strategy/MarshmallowNetworkObservingStrategy.java	100% <ø> (ø)	⬆️
...chen/reactivenetwork/library/rx2/Connectivity.java	68.14% <ø> (ø)	⬆️

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[pwittchen]

Looks reasonable. Thanks! I'll include this change in the next release. :)

[pwittchen]

@ychescale9 this update is available in the latest release 3.0.3

[ychescale9]

@pwittchen Thanks! That was quick:)

[pwittchen]

That's the way it should be :).

@ychescale9 Just being curious: can you tell me in what app are you using this library or can you send any link here?

[ychescale9]

@pwittchen Sorry just noticed your comment after 3 months 😂.

It was a cryptocurrency app (I've now moved on) with support for syncing blockchain data to the mobile client using ElectrumX servers.

ReactiveNetwork was an important piece in our networking stack as we need a stream of Network On / Network Off events for performing health check on our Sync Engine and decides when to retry / re-trigger the next sync etc.

I've also used it in other projects and I love it as it fits well within reactive / push-based architectures. ❤️