chore(deps): bump io.reactivex.rxjava3:rxjava in /app

Bumps [io.reactivex.rxjava3:rxjava](https://github.com/ReactiveX/RxJava) from 3.1.4 to 3.1.8.
- [Release notes](https://github.com/ReactiveX/RxJava/releases)
- [Commits](ReactiveX/RxJava@v3.1.4...v3.1.8)

---
updated-dependencies:
- dependency-name: io.reactivex.rxjava3:rxjava
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

app/build.gradle

@@ -44,7 +44,7 @@ dependencies {
     // have the latest features and bug fixes.
     implementation "com.google.android.gms:play-services-maps:18.0.2"
     implementation 'com.google.android.libraries.places:places:2.5.0'
-    implementation 'io.reactivex.rxjava3:rxjava:3.1.4'
+    implementation 'io.reactivex.rxjava3:rxjava:3.1.8'
 
     //implementation project(":maps-rx")
     implementation "androidx.appcompat:appcompat:1.4.1"