build(deps): bump org.robolectric:robolectric from 4.14.1 to 4.15

Bumps [org.robolectric:robolectric](https://github.com/robolectric/robolectric) from 4.14.1 to 4.15.
- [Release notes](https://github.com/robolectric/robolectric/releases)
- [Commits](robolectric/robolectric@robolectric-4.14.1...robolectric-4.15)

---
updated-dependencies:
- dependency-name: org.robolectric:robolectric
  dependency-version: '4.15'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -28,7 +28,7 @@ moshi = "1.15.2"
 navigationFragmentKtx = "2.9.0"
 okHttp = "4.12.0"
 retrofit = "3.0.0"
-robolectricVersion = "4.14.1"
+robolectricVersion = "4.15"
 roomKtx = "2.7.2"
 rx = "3.0.1"
 glide = "4.16.0"