Bump robolectric from 4.5.1 to 4.6.1

Bumps [robolectric](https://github.com/robolectric/robolectric) from 4.5.1 to 4.6.1.
- [Release notes](https://github.com/robolectric/robolectric/releases)
- [Commits](https://github.com/robolectric/robolectric/compare/robolectric-4.5.1...robolectric-4.6.1)

---
updated-dependencies:
- dependency-name: org.robolectric:robolectric
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

dependencies.gradle

@@ -38,7 +38,7 @@ ext.versions = [
         mockitoKotlin        : "3.2.0",
         kluent               : "1.64",
         apacheCodecs         : "1.15",
-        robolectric          : "4.5.1",
+        robolectric          : "4.6.1",
         dexter               : "6.2.2",
         timber               : "4.7.1",
         fastScroll           : "2.0.1",