Merge pull request #8900 from nextcloud/dependabot/gradle/mockitoVersion-3.12.4

Bump mockitoVersion from 3.11.2 to 3.12.4

build.gradle

@@ -61,7 +61,7 @@ ext {
     markwonVersion =  "4.6.2"
     prismVersion = "2.0.0"
     androidLibraryVersion = "master-SNAPSHOT"
-    mockitoVersion = "3.11.2"
+    mockitoVersion = "3.12.4"
     mockkVersion = "1.10.4"
     powermockVersion = "2.0.9"
     byteBuddyVersion = "1.11.15"