chore(deps): bump rxjava from 2.2.12 to 2.2.13 (#2375)

Bumps [rxjava](https://github.com/ReactiveX/RxJava) from 2.2.12 to 2.2.13.
- [Release notes](https://github.com/ReactiveX/RxJava/releases)
- [Changelog](https://github.com/ReactiveX/RxJava/blob/v2.2.13/CHANGES.md)
- [Commits](ReactiveX/RxJava@v2.2.12...v2.2.13)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

app/build.gradle

@@ -185,7 +185,7 @@ dependencies {
     // RxJava
     implementation 'io.reactivex.rxjava2:rxandroid:2.1.1'
     implementation 'io.reactivex.rxjava2:rxkotlin:2.4.0'
-    implementation 'io.reactivex.rxjava2:rxjava:2.2.12'
+    implementation 'io.reactivex.rxjava2:rxjava:2.2.13'
     implementation 'com.squareup.retrofit2:adapter-rxjava2:2.6.2'
 
     // Picasso