Bump workVersion from 2.5.0 to 2.6.0

Bumps `workVersion` from 2.5.0 to 2.6.0.

Updates `work-runtime` from 2.5.0 to 2.6.0

Updates `work-rxjava2` from 2.5.0 to 2.6.0

Updates `work-testing` from 2.5.0 to 2.6.0

---
updated-dependencies:
- dependency-name: androidx.work:work-runtime
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: androidx.work:work-rxjava2
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: androidx.work:work-testing
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

app/build.gradle

@@ -167,7 +167,7 @@ ext {
     parcelerVersion = "1.1.13"
     powermockVersion = "2.0.9"
     retrofit2Version = "2.9.0"
-    workVersion = "2.5.0"
+    workVersion = "2.6.0"
     markwonVersion =  "4.6.2"
 }