chore(deps): bump rxjava from 2.2.6 to 2.2.7 (#1184)

Bumps [rxjava](https://github.com/ReactiveX/RxJava) from 2.2.6 to 2.2.7.
- [Release notes](https://github.com/ReactiveX/RxJava/releases)
- [Changelog](https://github.com/ReactiveX/RxJava/blob/2.x/CHANGES.md)
- [Commits](ReactiveX/RxJava@v2.2.6...v2.2.7)

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

app/build.gradle

@@ -136,7 +136,7 @@ dependencies {
 
     // RxJava
     implementation 'io.reactivex.rxjava2:rxandroid:2.1.1'
-    implementation 'io.reactivex.rxjava2:rxjava:2.2.6'
+    implementation 'io.reactivex.rxjava2:rxjava:2.2.7'
     implementation 'com.squareup.retrofit2:adapter-rxjava2:2.4.0'
 
     // Picasso