Bump robolectric from 4.5.1 to 4.7.3

Bumps [robolectric](https://github.com/robolectric/robolectric) from 4.5.1 to 4.7.3.
- [Release notes](https://github.com/robolectric/robolectric/releases)
- [Commits](robolectric/robolectric@robolectric-4.5.1...robolectric-4.7.3)

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

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

Author: dependabot[bot]

owncloudComLibrary/build.gradle

@@ -15,7 +15,7 @@ dependencies {
     kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshiVersion"
 
     testImplementation 'junit:junit:4.13.2'
-    testImplementation 'org.robolectric:robolectric:4.5.1'
+    testImplementation 'org.robolectric:robolectric:4.7.3'
 }
 
 android {