Bump io.reactivex.rxjava3:rxjava from 3.1.7 to 3.1.8 (#94)

Bumps [io.reactivex.rxjava3:rxjava](https://github.com/ReactiveX/RxJava) from 3.1.7 to 3.1.8.
- [Release notes](https://github.com/ReactiveX/RxJava/releases)
- [Commits](ReactiveX/RxJava@v3.1.7...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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

build.gradle

@@ -46,7 +46,7 @@ repositories {
 }
 
 dependencies {
-    implementation "io.reactivex.rxjava3:rxjava:3.1.7"
+    implementation "io.reactivex.rxjava3:rxjava:3.1.8"
     testImplementation "org.reactivestreams:reactive-streams-tck:1.0.4"
     testImplementation "org.testng:testng:7.6.0"
     testImplementation "com.beust:jcommander:1.82"