Merge pull request #7501 from nextcloud/dependabot/gradle/mockitoVersion-3.6.28

Bump mockitoVersion from 3.6.0 to 3.6.28

build.gradle

@@ -61,7 +61,7 @@ ext {
     prismVersion = "2.0.0"
     butterknifeVersion = "10.2.3"
     androidLibraryVersion = "master-SNAPSHOT"
-    mockitoVersion = "3.6.0"
+    mockitoVersion = "3.6.28"
     mockkVersion = "1.10.2"
     powermockVersion = "2.0.9"
     byteBuddyVersion = "1.10.18"