Bump rxjava from 3.0.0-RC5 to 3.0.0-RC6 (#10)

Bumps [rxjava](https://github.com/ReactiveX/RxJava) from 3.0.0-RC5 to 3.0.0-RC6.
- [Release notes](https://github.com/ReactiveX/RxJava/releases)
- [Commits](ReactiveX/RxJava@v3.0.0-RC5...v3.0.0-RC6)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

build.gradle

@@ -50,7 +50,7 @@ repositories {
 
 dependencies {
     implementation "io.reactivex.rxjava2:rxjava:2.2.15"
-    implementation "io.reactivex.rxjava3:rxjava:3.0.0-RC5"
+    implementation "io.reactivex.rxjava3:rxjava:3.0.0-RC6"
     testImplementation 'junit:junit:4.12'
 }