Bump androidx.work:work-runtime-ktx from 2.7.1 to 2.8.1

Bumps androidx.work:work-runtime-ktx from 2.7.1 to 2.8.1.

---
updated-dependencies:
- dependency-name: androidx.work:work-runtime-ktx
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

app/build.gradle

@@ -120,7 +120,7 @@ dependencies {
         exclude module: 'xpp3'
     }
     implementation "androidx.work:work-runtime:2.7.1"
-    implementation "androidx.work:work-runtime-ktx:2.7.1"
+    implementation "androidx.work:work-runtime-ktx:2.8.1"
 
     implementation 'com.google.android.play:core:1.10.3'
     implementation 'android.arch.lifecycle:common-java8:1.1.1'